Optimised response characteristics and large reserves create very good road adhesion for great grip and high comfort. These suspension struts with reservoirs permit infinite adjustment of the spring pretensioning, a 22-position adjustment of the traction level and a 22-position adjustment of the pressure level, split between the high and low speed range (short surface irregularities / long strut movements e.g. on traffic bumps). The reservoir with pressure level adjustment is located directly on the suspension strut on the 632/642 and 633/643 versions, while on the 631/641 versions it is connected with a hose and can be fitted flexibly. The Classic version is the same as the "normal" version except that it has a black spring instead of a blue one. Approval: with operating licence (Germany only). As an option, the suspension struts can also be ordered at extra cost with height adjustment (629) and/or hydraulic spring pretensioning (625). Wilbers products can be used for repairs and maintenance.