The Lockwood Modular Cylinder Extensions provide a simple and effective method of producing an extended cylinder. Extended cylinders are often required where there is a door thickness of 50 mm or greater, or when the mortice lock is mounted off centre in the door. The extra length in the cylinder is required to bring the face of the cylinder out from the door and escutcheon to enable use of the key.

Virtually any length cylinder can be made by stacking as many or as few extension pieces as required together and screwing them into the back of a special extended cylinder base. The desired cam required for the special lock function is attached to the end of the extended cylinder and then it is ready for installation.

A special extended base cylinder is required as it has two tapped holes in the back of the cylinder to accept the assembly screws to retain the extension kits. These cylinders use the standard 570 type barrel.