Yale Y3 Night latch is a ergonomic design based on the original Yale P77 model. The internal knob and snib button provides a convenient way to operate the lock from inside the property. Yale Y3 Contemporary Night latch bolt is immediately engaged as soon as you close the door and can also be held back temporarily with the snib button, in case you need to leave the door open whilst bringing in the shopping. The internal knob is used to operate the lock from the inside and can be deadlocked by the snib button for additional overnight security. The external 5 pin rim cylinder lock is manufactured to a good specification, is tested for resistance to corrosion and a minimum of 100,000 usage cycles.