3 Lever Mortice Sashlocks from Perry are adjustable and suitable for use on left or right hinged timber doors. This Sashlock is suitable for sprung lever handles or knobs. The key can be operated from both sides and suits doors up to 54mm thick.
Backset is the measurement used to work out the distance the keyhole needs to be from the edge of the door:
63mm Sashlock has a backset of 45mm
75mm Sashlock has a backset of 59mm