Street Tuned Suspension System 24 levels of dampening adjustability. IP F.A. 5W damper oil.Mono-tube shock design. JIS G3445-STKM13C (DIN2393-ST44-2) carbon steel 52mm diaseamless tube. 44mm linear characteristic internal piston. Cold-bent springs made from high strength SAE9252 steel. Lower bracket height adjustability prevent the need to adjust the spring perch, offering the maximum shock-absorbing travel. Powder painted steel lower bracket can match all design of brake line and ABS line holder, easy for installing. Specifications: Topmount Rear