Half Cylinder

A Half Cylinder, sometimes called a Single Cylinder, is half the length of a regular cylinder. One side works with a key while the other side is blank, great when you only want to lock the door from one side.

Thumbturn

This type of cylinder works well on back doors or patio doors. On the outside the cylinder is locked by a key while on the inside you just need to twist the thumbturn. A Thumbturn Cylinder is also useful in an emergency when a quick exit is required - simply twisting the thumbturn will unlock the door.

Offset Cylinders

Most people need cylinders that are equal, which means from the centre screw hole, each side is exactly the same dimension.

On an Offset Cylinder, the external size to centre [A] and internal size to centre [B] are different, in our example measuring 30mm and 50mm. This type of cylinder is most commonly used on UPVC or Composite doors.

To measure an Offset Cylinder, check our measuring guide.