Spring loaded camming device

A spring loaded camming device (also SLCD or just cam) is a piece of rock climbing or mountaineering protection equipment. It consists of two, three, or four cams mounted on a common axle or two adjacent axles, so that pulling on the axle forces the cams to spread further apart. The SLCD is used by pushing on the cam via a pull "trigger" (a small handle) so the cams move together, then inserting it into a crack or pocket in the rock and pulling on the "stem", a rod attached to the axle. This makes the cams expand and hold onto the rock face, and it is held lightly in position by small springs. At this point the climbing rope can be attached to a sling and carabiner at the end of the stem.

Popular brands include Friends (the first commercial brand), Camalots, and Aliens.