Discount code SPRING26
Spring Sale
5% Off Everything
Code: SPRING26

CISA Astral S - Euro Double Cylinder 50 - 50 (100mm Polished Brass)

£54.72
Customer Reviews
Rated 4.8

/5

Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5
58 Reviews

100%

Recommended
this Product
Ease of Use
Out of 5
4.9
Build Quality
Out of 5
4.9
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Chris Long Verified Customer

I ordered this item as our previous lock had started to play up. It arrived very quickly and very well packed.

Instructions were very clear, and in a few minutes I had successfully removed the old lock and replaced it with the new one. Since the new lock has been fitted it has worked perfectly, without any problems or issues. It looks to be a very well designed and manufactured lock, and it feels as though it will give us better security than the lock that it replaced. All in all a very good value purchase and well worth the money paid for it.

Read more
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
CAA 3 Verified Customer

Fitted in 10 minutes,no problems at all,security side not tried,no one attempted to break in yet,but it appears a solid lock,it was suggested to me by a retired locksmith.

The cost of the lock was very competitive,no problems with delivery which was fast considering,problems with Royal Mail.

Would have no hesitation in recommending both Safe as a company and

Cisa as a brand if looking to replace a lock.

Read more

See all reviews

Discount code SPRING26
5% Off Everything
Code: SPRING26
View Full Specification
  • Anti-Snap protection by way of strong laminate core.
  • Employs Anti Pick, Anti Drill & Anti Bump for extra security.
  • High security TS007 1 Star Rated.
  • Just need keys? We also sell Spare CISA Astral S Keys.
  • Cylinder Length: 100mm
  • Size to Centre (ext): 50mm
  • Size to Centre (int): 50mm
  • Reversible, allowing either side to be used externally.
  • Multiple locks can be keyed alike allowing the same key to operate each lock.
MPN: OA3S1 5050 PB

Keyed Alike Cylinder Packs

Build Your Custom Pack >


See all reviews

Details
Product Diagram with Dimensions
A 50mm
B 50mm
C 100mm
Dimensions
Size Centre (external) 50mm
Size Centre (internal) 50mm
Overall Length 100mm
Cylinder is reversible allowing either side to be used externally
Show Imperial »
Key Features
Product Code
CIS-ASTS-5050-EU/PB
Manufacturer Part Number
OA3S1 5050 PB
Cylinder Type
Euro Double
Lock Mechanism
10 Pin Cylinder
Equal / Offset
Equal
Colour
Polished Brass
Security & Ratings
Security Level
High
Anti-Snap
Yes Laminate Core
Security Measures
Anti Pick, Drill & Bump
Code Card
Yes
Kitemarked
Yes
TS Star Rating
1 Star (TS007)
British Standard
BS EN 1303:2005
Fire Rating
No
* Insurance approval may vary due to conditions and location. Please check with your insurance provider.
Features
Inside Key
Yes
Symmetrical Key
Yes
Keyed Alike
20 sizes available
In The Box
Cylinder
Yes
Retaining Screw
Yes
Keys
3
Reviews [58]
Rated 4.8

/5

Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5
58 Reviews

100%

Recommended
this Product
Ease of Use
Out of 5
4.9
Build Quality
Out of 5
4.9
Sort by:
Trevor Verified Customer January 2016
Rated 4.1 / 5Rated 4.1 / 5Rated 4.1 / 5Rated 4.1 / 5Rated 4.1 / 5
Recommended

These are well made, robust cylinders that look and feel secure.

Was this helpful? 23

Anonymous Verified Customer January 2016
Rated 4.4 / 5Rated 4.4 / 5Rated 4.4 / 5Rated 4.4 / 5Rated 4.4 / 5
Recommended

It was exactly what I wanted

Was this helpful? 22

Anonymous Verified Customer February 2020
Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5
Recommended

I've used these locks before on previous properties and have always been happy with them. I chose 2 barrels with 4 keyed-alike keys. All work perfectly and I'm happy with the increased security they provide.

Was this helpful? 21

Chris Long Verified Customer February 2016
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

I ordered this item as our previous lock had started to play up. It arrived very quickly and very well packed.

Instructions were very clear, and in a few minutes I had successfully removed the old lock and replaced it with the new one. Since the new lock has been fitted it has worked perfectly, without any problems or issues. It looks to be a very well designed and manufactured lock, and it feels as though it will give us better security than the lock that it replaced. All in all a very good value purchase and well worth the money paid for it.

Was this helpful? 21

Anonymous Verified Customer May 2016
Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5Rated 4.8 / 5
Recommended

Good price easy to fit.

Was this helpful? 20

CAA 3 Verified Customer November 2022
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

Fitted in 10 minutes,no problems at all,security side not tried,no one attempted to break in yet,but it appears a solid lock,it was suggested to me by a retired locksmith.

The cost of the lock was very competitive,no problems with delivery which was fast considering,problems with Royal Mail.

Would have no hesitation in recommending both Safe as a company and

Cisa as a brand if looking to replace a lock.

Was this helpful? 18

Daves Verified Customer September 2022
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

Since I started using Cisa locks at the University I worked at, I have now installed them on all my house locks. Keys are so much more secure than standard Yale type and not orientation specific, which is great when having cold and or wet fingers. This Euro lock took just a few minutes to install.

Was this helpful? 18

Roby Verified Customer September 2022
Rated 3.8 / 5Rated 3.8 / 5Rated 3.8 / 5Rated 3.8 / 5Rated 3.8 / 5
Recommended

I purchased this CISA Astral S - Euro Double Cylinder 45 - 50 for our porch as we got already several CISA Astral S cylinders on the external doors. The ones I purchased before are very good ones, but the newly purchased one was not build properly, as if the key is inserted all the way (as usual), you cannot turn it! You need to leave a gap of approx 1mm in order to allow the key to turn and open the door. Same problem on both sides of thy cylinder, quite disappointed.

Was this helpful? 18

Anonymous Verified Customer June 2015
Rated 3.5 / 5Rated 3.5 / 5Rated 3.5 / 5Rated 3.5 / 5Rated 3.5 / 5
Recommended

It was easy to fit, normal Euro lock fittings.

All the keys I had cut fit perfectly, not issues.

Like any other locks, only time will tell if the.

Was this helpful? 18

Anonymous Verified Customer February 2023
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

Super

Was this helpful? 17

Terry Verified Customer March 2026
Rated 4.6 / 5Rated 4.6 / 5Rated 4.6 / 5Rated 4.6 / 5Rated 4.6 / 5
Recommended

The Astral S appears to be sturdy and was easy to fit. You may need to cut down the bolt that secures the lock to the door. I used the old bolt to save doing this.

The orientation of the lock was horizontal rather than vertical but that doesn’t present a problem. Can’t comment on security as until someone tries to force it you can’t know.

Was this helpful?  

Anonymous Verified Customer December 2025
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

This is ideal cylinder to use if you have elderly relative who keeps leaving key in lock on inside of door! This is the only decent secure cylinder I could find that has a clutch inside so that we can still unlock the door with key from outside if a key is in lock on the inside. Perfect - especially in an emergency situation where we need to get in house quickly.

Was this helpful?  

Anonymous Verified Customer November 2025
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

We bought the CISA Astral S - Euro Thumbturn Cylinder 35 - 35 and are very happy with it. It was very easy to install, arrived in a good time, great quality and comes with 3 sets of keys. I originally ordered the wrong size and Safe were great helping me with the return and getting the right size out. Would recommend, especially the thumbturn mechanism - easy to use.

Was this helpful?  

Anonymous Verified Customer September 2025
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

Excellent secure lock, easy to fit as its a Euro lock

Was this helpful?  

Anonymous Verified Customer July 2025
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

No issue with installing the lock, behaves just like any other cylinder locks. The thumbturn was a nice upgrade from the mortice lock I had before. Keys seem sturdy, though had to remind family that the key hole should point to the left (as they're used to it pointing down), lest they try to yank the key out.

Was this helpful?  

Anonymous Verified Customer December 2024
Rated 4.2 / 5Rated 4.2 / 5Rated 4.2 / 5Rated 4.2 / 5Rated 4.2 / 5
Recommended

I've bought this lock because I wanted to be able to get in from the outside even if a key was into the lock on the inside, and that works perfectly. It's of course more secure than an ordinary lock as the key cannot be duplicated without the card.

Very easy to fit with just one screw to take out and screw back in.

Difficult to say how secure it is against break ins: I can only trust the description for that.

It is a bit on the expensive side: I've bought a similar product in Spain for about half the price.

Was this helpful?  

David Verified Customer September 2024
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

Very happy with the advice given for a suitable product. I needed quite a specific cylinder in tens of dimensions and features and they helped me find exactly what I needed. Did exactly what I was looking for - very happy all round. I would definitely still advise and return to Safe.co.uk in the future.

Was this helpful?  

Anonymous Verified Customer December 2023
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

I found the advice over the phone helpful. The unit is perfect and matches the handle although the handle is a different make. I needed just a bit of help fitting it, as it is not something I have done before (pensionable and female, that's my excuse). Thank you for prompt delivery.

Was this helpful? 2

David Kirton Verified Customer October 2023
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

The cylinder was a perfect fit, flush with my handles both sides for added security and assists in preventing cylinder snapping.

Was this helpful? 14

David Verified Customer August 2023
Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5Rated 5 / 5
Recommended

I have used 6 pin locks in the past, but this is a totally different product. The build quality is good and there is no possibility of "picking" it like with a standard Euro lock so I'm totally satisfied that the small price difference is worth it to upgrade the security to this level. Fitting is extremely simple and it can replace any standard Euro lock in less than 5 minutes, so totally happy with this purchase. Safe is the best value place to get them as well.

Was this helpful? 16

Accessories

Add at Checkout

Thumbnail of Avocet ABS Lock Lubricant

ABS Lock Lubricant

Advanced lock lubricant in a 200ml aerosol spray with applicator nozzle that cleans, lubricates, and protects to extend the life of your high security locks.
£12.95
£16.50 Save £3.55
Thumbnail of CISA Astral S Spare Cut Key

Spare Key

Keys are included as standard, but we can cut you a spare.
Please allow 7 additional days for delivery.
£6.95
Delivery

Select during checkout


Filter by
Popular Delivery Options  
Royal Mail 48 Our standard Royal Mail 48-hour service Text to confirm delivery time Text to confirm delivery time
Mon-Fri
1 - 2 days
8am - 6pm
FREE
Mon-Fri
1 - 2 days
8am - 6pm
FREE
Next / Named Day Delivery to your front door on a day of your choice
Mon-Fri
8am - 6pm
£5.00
Mon-Fri
8am - 6pm
£5.00
Scottish Highlands Delivery Includes doorstep drop off deliveries to the following Highlands post codes, no steps: AB30-38, AB44-56, FK17-99, G83, IV1-39, IV52-54, IV63, KW1-14, PA21-33, PA34-40, PH18-26, PH30-41, PH49-50
Mon-Fri
1 - 3 days
8am - 6pm
FREE
Mon-Fri
1 - 3 days
8am - 6pm
FREE
Isle of Wight Delivery Our standard doorstep drop off service, no steps
Mon-Fri
1 - 3 days
8am - 6pm
FREE
Mon-Fri
1 - 3 days
8am - 6pm
FREE
Isle of Man Delivery Our standard doorstep drop off service, no steps
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Isles of Scilly Delivery Our standard doorstep drop off service, no steps
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Scottish Islands Delivery Includes doorstep drop off deliveries to the following Scottish Island post codes, no steps: HS1-9, IV40-51, IV55-56, KA27-28, KW15-17, PA20, PA41-49, PA60-78, PH42-44, ZE1-3
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Northern Ireland Delivery Our standard doorstep drop off service, no steps
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Guernsey Delivery Our standard doorstep drop off service, no steps
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Jersey Delivery Our standard doorstep drop off service, no steps
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Mon-Fri
2 - 3 days
8am - 6pm
FREE
Tail Lift Delivery Options
Indoor Delivery Options
Delivery & Install Options
Returns

Returns

Replacements
If you are not completely satisfied with your purchase, simply complete our returns form within 14 days of receiving your order. Goods must be returned within 30 days of the delivery date, in their original condition and packaging.
More information about returns
FAQs [4]

FAQs (4)

» Ask Question   

 
If your door is closed and the key is in the lock internally, can you unlock the door from outside with second key?
Neville, Punchard
Yes, all of the CISA Astral S 10 Pin - Euro Double Cylinder Series have the facility to unlock with a second key from the outside.
Jonathan P
Was this helpful? 76
 
1. How could I obtain spare keys in future?
2. Please confirm if possible - barrel diameter is 17mm, total height is 33mm, width of keel (the bar at the bottom) 10mm. With thanks.
Richard, Lenora
The CISA Astral S Cylinders are supplied with a unique code card which allows you to order additional keys and keyed alike locks by providing the code on the card. All Euro Profile cylinders have the same face dimensions - 17 x 33 x 10mm.
Jonathan P
Was this helpful? 69
 
Can two locks with different sizes have key-alike?
Zoe, London
Providing the locks are of the same brand with the same number of pins, lock cylinders can be keyed alike despite the overall length being different.
Phil R
Was this helpful? 61
 
Are the spare keys you offer for this lock original CISA blanks?
Frazer Dunn, Glasgow
Keys cut would be from an original CISA blank.
Tom W
Was this helpful? 44
Help & Advice

Related Blog Articles

Get in Touch

We're here Mon-Fri, 9am-5pm.


Pay Later

Pay in 30 Days

Get your goods before you pay with Pay in 30 Days by Klarna. Sit back and relax and let Klarna notify you when payment is due. More information

Rep. APR (variable) 0%
Pay Now £0.00
Pay 23rd May £54.72
Total Payable £54.72

Pay in 3

Spread the cost of your purchase into 3 interest-free instalments. The first payment is made at point of purchase, with remaining instalments scheduled automatically every 30 days. More information

Now £18.24
23rd May £18.24
22nd Jun £18.24

The Safe Shop Ltd. is authorised and regulated by the Financial Conduct Authority (FCA FRN 915388) and acts as a credit intermediary and not a lender, offering credit products provided exclusively by Klarna Financial Services UK Limited.

Please note that the following products are not regulated by the FCA: Pay in 30 days and Pay in 3 instalments. Borrowing more than you can afford or paying late may negatively impact your financial status and ability to obtain credit.

Finance is only available to permanent UK residents aged 18+, subject to status, terms and conditions apply.

The Safe Shop Ltd., 1 Strand Street West, Preston, Lancashire PR2 2NS

Keyed Alike

Keying Options

Keyed to Differ or Keyed Alike locks?

As standard the CISA Astral S - Euro Double Cylinder 50 - 50 (100mm Polished Brass) is supplied Keyed to Differ which means the lock includes a set of keys that are unique and will only open this lock. If you require multiple locks you can choose to have them all Keyed Alike, meaning that each lock can be opened using the same key. You can view this cylinder keyed alike here.

What is Keyed to Differ?

  • Keyed to Differ is the standard way a lock is supplied.
  • Each lock is opened by its own unique key.
  • Each lock includes a unique set of keys.
  • Covered by our returns policy.

What is Keyed Alike?

Our Keyed Alike Cylinder Packs make it easy to create your own custom cylinder lock and key solution - allowing up to 99 keys to unlock any combination of different-sized cylinder locks.

The possibilities are endless - from having one key per family member unlocking the front door, kitchen and patio doors, right up to large-scale company storage keying options.

  • Each key can open multiple locks - the same key could unlock your house and office.
  • Locks need to be the same brand and number of levers.
  • Keyed Alike locks include one set of keys regardless of how many locks are purchased.
  • Made to order so NOT covered by our returns policy.

Keyed Alike Packs

Build Your Custom Pack >