Protection devices

Protection devices, collectively known as rock protection or pro, provide the means to place temporary anchor points on the rock. These devices may be categorized as passive (nuts, Hexentrics, etc.) or active spring-loaded camming devices (SLCDs).

Nuts
Nuts are manufactured in many different varieties. In their simplest form, they are just a small block of metal attached to a loop of cord or wire. The most popular styles are tapers and hexcentrics. They are sometimes referred to by the slang term, wires.

Nuts are used by simply wedging them into narrowing cracks in the rock, then giving them a tug to set them.

Hexcentrics
Hexcentrics, usually called hexes, are a type of nut, a hollow eccentric hexagonal prism with tapered ends, usually threaded with tape. They are manufactured by several firms, with a range of sizes varying from about 10mm thick to 100mm wide. Sides may be straight or curved.



Spring loaded camming devices
These consist of three or four cams mounted on a common axle or two adjacent axles, in such a way that pulling on the shaft connected to the axle forces the cams to spread further apart. The SLCD is used like a syringe, by pulling the cams via a "trigger" (a small handle) which forces them closer, inserting it into a crack or pocket in the rock, and then releasing the trigger. The springs make the cams expand and grip the rock face securely. A climbing rope may then be attached to the end of the stem via a sling and carabiner.

Tricams
A Tricam is a passive or active device consisting of a shaped aluminium block attached to a length of tape (webbing). The block is shaped so that pulling on the tape makes it cam against the crack, gripping the rock tighter. It requires careful placement so that it does not loosen when not loaded. It is generally not as easy to place or remove as a SLCD but is much cheaper and lighter, and is the only thing that will work in some situations like quarry drill-holes and limestone pockets. The smaller sizes can work well in old piton scars. They can also be used Passively as nuts.