PM320 3 Lever Mortice Sashlock Polished Brass 65mm 2.5in
Finish: Polished Brass Case Size: 65mm x 101mm (2 1/2 in) Backset: 45mm 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.