for connection to a backplate Sidemount harness The most basic sidemount harness is little more than cylinders fitted with belt loops and slid onto the standard caver's belay or battery belt along with any extra weights needed to achieve neutral buoyancy, and a caver's belt mounted battery pack. This simple configuration is particularly low profile and suited to small cylinders. A more complex but still minimalist system is a webbing harness with shoulder straps, waist belt and crotch strap, supporting a variety of sliders and D-rings for attachment of cylinders and accessories, with or without integrated weighting or separate weight belts, and with or without a back mounted buoyancy compensator, which may be attached to the harness, or directly to the diver. Cylinders are usually attached to a shoulder or chest D-ring and waist belt D-ring on each side. Accessories In most scuba sets, a buoyancy compensator (BC) or buoyancy control device (BCD), such as a back-mounted wing or stabilizer jacket (also known as a "stab jacket"), is built into the harness. Although strictly speaking this is not a part of the breathing apparatus, it is usually connected to the diver's air supply, to provide easy inflation of the device. This can usually also be done manually via a mouthpiece, in order to save air while on the surface, or in case of a malfunction of the pressurized inflation system. The BCD inflates with air from the low pressure inflator hose to increase the volume of the scuba equipment and cause the diver gain buoyancy. Another button opens a valve to deflate the BCD and decrease the volume of the equipment and causes the diver to lose buoyancy. Some BCDs allow for integrated weight, meaning that the BCD has special pockets for the weights that can be dumped easily in case of an emergency. The function of the BCD, while underwater, is to keep the diver neutrally buoyant, i.e., neither floating up or sinking. The BCD is used to compensate for the compression of a wet suit, and to compensate for the decrease of the diver's mass as the air from the cylinder is breathed away. Diving weighting systems increase the average density of the scuba diver and equipment to compensate for the buoyancy of diving equipment, particularly the diving suit, allowing the diver to fully submerge with ease by obtaining neutral or slightly negative buoyancy. Weighting systems originally consisted