Optimized response and great reserves ensure a secure road holding performance for grip with maximum comfort. These shock absorbers with reservoir enable continuous adjustment of the spring preload, a 22-fold adjustment of the rebound and a 22-fold compression adjustment separately for high-and low-speeds (short uneven distances / long spring movements, for example on bumpy surfaces). The reservoir with the compression setting is located directly on the shock absorber in the 632/642 and 633/643 versions, in the case of 631/641 versions it is connected with a hose and can be mounted more flexibly. The 643Q model has the reservoir mounted cross to the shock absorber, the 643QS is a swiveling version for easier installation. The Classic version is equivalent to the"normal", it however has a black spring instead of a blue one. Approval: ABE-type approval. The shock absorbers can be optionally supplied with a height adjustment (629) and / or hydraulic spring preload (625) at a surcharge.