Specification: Spring: coil with preload regulator Stroke: 50mm Diameter: 27.2 X 350 / 400mm, 31.6X 350 / 400mm Spring: coil with preload regulator Φ31.6 is hard spring Φ27.2 is soft spring Seat tube / seat post reducing sleeve 27.2 turns 28.6 / 30.1 / 30.4 / 30.8 / 31.6 / 33.9 Note: A to B means to transform the small diameter A into a small thick diameter B. The size of the reducing sleeve is, for example, 27.2 to 31.6 and the inner diameter of the reducing sleeve is 27.2 and the outer diameter is 31.6. whereby the thin seat tube 27.2 can become the thick seat tube 31.6. The thick inner diameter of the center tube of 31.6 still uses the thin seat tube of 27.2 through the reducing sleeve. Backward movement distance: 25 mm Backward distance: 25mm Applicable models: mountain bike / recreational vehicle / mountain bike Package: 1 x bicycle seat post