"From The Anvil" Spring Unit Cassette
It converts unsprung handles to spring action. It is cut into the door below the back plate either on one or two sides. So if you have a poor lock and you want our handles to work perfectly this is the answer. This cassette is designed to increase the tension and performance of an old or weak lock.
Size: 2 inch x 1 3/8 inch (51mm x 35mm)