The harness usually includes a buoyancy compensator bladder. This class of buoyancy aid is known as a buoyancy control device or buoyancy compensator. Scuba divers commonly wear a buoyancy compensator, which has an inflatable gas chamber. The major cause of reduced felt recoil is a compensator, or muzzle brake. There was also a recoil compensator built into the muzzle. In order to absorb axial thermal expansion loads, it is equipped with a bellows compensator. A failure of the buoyancy compensator would be exacerbated. In 8% of cases the buoyancy compensator malfunctioned. A static var compensator can also be used for voltage stability. Similar devices include the static synchronous compensator (STATCOM) and Unified Power Flow Controller (UPFC). The Model 44 could also be obtained with a "Power Control" barrel compensator. Brake compensator fitted on petrol models. The closed bottom port of the M16A2 design makes the device function as a compensator. Aftermarket kits were also available, such as the EMPI Camber Compensator, for the knowledgeable owner. This is the basic principle behind a linear compensator.