Lightweight. Constructed from ultra-light and strong aluminum alloy. Weight: about 530g How to choose the size: 1. Check the diameter of the original seat post, choose the same size as the original diameter. 2. Measure the inner diameter of the frame tube. Color: silver Material: aluminum alloy Size: 27.2 x 300 mm Package Contents: 2 x Bicycle Seat Post Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in a little different from the real thing. The measurement allowed error is +/- 1-3 cm.