Climbing is an exhilarating and adventurous sport which requires endurance and stamina. Due to the nature of the sport there is more risk of injury than most other activities. This makes having the right protective equipment (or pro) that much more important. There is no one single piece of equipment that will ensure your safety; a combination of equipment is necessary to prevent injury or fatality.
Cams are devices that you place into cracks or holes to provide protection from falls. They are spring-loaded so as to expand and hold when they are inserted and pressure is applied; the more pressure that is applied, i.e. your body weight, the harder they grip. They come in a variety of sizes so as to fit in various sizes of cracks and holes.
From the cam, a karabiner (or biner) is attached. A biner is a ring with a spring opening and it is used to attach your ropes and harness. D-rings are a type of biner which is ultra strong to hold your weight and prevent your from falling.
Another basic type of pro is the nut which is small and usually in the shape of a nut. They have a hole through which a cable is threaded to attach another piece of equipment such as a...