Union 2242 2 Lever Mortice Rebated Sash Lock Electro Brass 65.5mm 2.5in

Forend Finish: Brass (Striking Plate Security box type, finished to match forend)
Case Size: 65.5mm x 102mm (2.5in)
Backset: 44.5mm 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.
Pack: Visi Pack