Junkers had a wind tunnel built and invented a hydraulic brake. EBD reduces the strain on the hydraulic brake force proportioning valve in the vehicle. There was also, from September 1946, a DMAH version, which featured hydraulic brake linkages. An autobrake is a type of automatic wheel-based hydraulic brake system for advanced airplanes. The GT included anti-lock braking system with electronic brakeforce distribution and hydraulic brake assistance. Hydraulic brake levers move a piston in a fluid reservoir. The hydraulic brake calipers were mounted directly onto the differential. In 2006 high-volume models such as the E-class returned to conventional hydraulic brake systems. In 1883, the Saint-Chamond hydraulic brake was introduced to better absorb recoil. The wheel has a hydraulic brake that is actuated by full application of the spoilers. Apart from this additional booster setup, the braking system is a normal hydraulic brake system. Initially a double-circuit hydraulic brake system was used, but later a single-circuit was used.