Features: 1. High-strength aerospace aluminum alloy tube, 50mm adjustable preload suspension travel, standard clamp with 2-bolts ensure safety in riding. Coil spring damping offer comfortable experience. Zoom is professional bike compnt manufacturer from Taiwan, the confident of high quality. No 1 market share in global. 2. Spring Coil Suspension Reduce Bump Impact: Build-in spring coil and damper rubber absorb the vibration while riding, the seat post comfort your riding experience, improve the shocks and pain immediately. Rebound force adjustable by tighten or loose the bottom screw. 3. Rebound Force Adjustable Clamp Angle Adjustable: You can adjust the bottom screw to change the spring rebound force fit to your weight to get best riding experience. Saddle clamp angle can adjust in -5 degree to +18 degree. 2 bolts hold the clamp, enhance safe and easy to install. 4. How to Choose the Size:1.Check your current seatpost diameter, size marked on lower position of the post (Need to take it out from tube to see the size mark). And buy same size from the option. 2.Measure the inside diameter of the frame tube. Suit for most Fixed Gear bike ,Road Bike ,Mountain Bike , Universal Bikes,etc.It fit for riders weight 50kg/ 110lbs to 180kg/ 397lbs Notice: Actual color may be slightly different from the image due to different monitor and light effect. Please allow 1-3cm deviation due to manual measurement. Material: Aluminum Alloy Brand: ZOOM Model number: SPS-405 Process: Frosted anode Color/Style: As the picture shown includes: choice 1: 1 x seat post choice 2: 1 x seat post, 1 x Adapter "