Measuring the diameter of the gu sliding door lock often goes wrong. The backset is measured from the front plate to the center of the crank hole. With a lift-and-slide door, the lift-and-slide lock is often 8 millimeters recessed into the wood. So the mistake is made by measuring from the front of the wood.

The pitch or PC size is the same for all lift and slide locks. The measurement therefore goes from the center of the crank to the center of the cylinder hole. For all lift locks this is 69 millimeters, so all lift and slide fittings fit here.