Rope rescue is a subset of technical rescue that involves the use of Rope, be it steel or cable rope, or more commonly used nylon, polyester, or other type of rope. Kernmantle (kern = core and mantle = sheath) rope as it is called, is available in various types: Dynamic (stretches to absorb the shock of a falling lead climber or rescue professional) or Static (actually low stretch) which is most commonly used in rescue and industrial rope work. Anchoring includes using specialty anchors, as well as things as simple as a length of chain, cable, rope, or webbing wrapped around a pillar, tree, boulder, or such. They provide the security and a point from which a person or subject (The word "victim" has dropped, and changed to "subject," due to the negative implications of the term "victim") can be belayed. Belaying is the act of protecting the climber, rescue professional, or subject in the event of a fall. Various other devices used, including: friction rappel [lowering] devices, which acts as a braking device on the rope. They are used for lowering a load, a subject or ones-self (rappelling). Pulleys can serve as a mechanical advantage, along with rope grabs, and other tools, to raise, or haul, a load up a vertical section, or across a gully or canyon. Pulleys systems are used in conjunction with the rope, rope grabbing devices, i.e.: Prusiks, or mechanical grabs, to capture the progress made during the lift. Since pulley systems are generally short in length, they are used in conjunction with a progress (raise) capturing technique, and a long rope; and a backup safety or belay. This specialized equipment is used to reach the subject(s) and safely recover them.