StrongBOLT 2200S BS 5 Lever Mortice Sashlock Satin Chrome 81mm Box

Finish: Satin Chrome

Case Size: 81mm x 109.6mm (3in)

Backset: 57mm This is the measurement from the edge of the door to the centre of the keyhole.

Centre: 57mm This is the measurement from the centre of the follower, which operates the handles, to the centre of the keyhole. In the UK this is commonly 57mm.
Boxed