Union J2200SP30 Strongbolt BS 5 Lever Mortice Sash Lock 81mm Satin Brass Box

Finish: Polished Brass
Case Size: 81mm x 109.6mm (3 in)
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