Spring Coil Suspension: Build-in spring coil and damper rubber absorb the vibration while riding, the seat post comfort your riding experience, improve the shocks. Rebound force adjustable by tighten or loose the bottom screw. Suspension travel 50mm. Pay Attention to Diameter Before Buy. Wrong diameter will not to install.They can be used with adapters to convert diameters. Easy to install and in use. Constructed of ultra light and strong aluminum alloy. Suit for most Fixed Gear bike ,Road Bike ,Mountain Bike , Universal Bikes,etc.It fit for riders weight 50kg / 110lbs to 180kg / 397lbs Types of: suspension seatpost Used for: Mountain Bike,road bike color:Black Material:aluminium alloy size: 30.4 x 350mm Package Contents: 1 x suspension seatpost Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.