1.[Specifications] The size of the bike seat post is 31.8/33.9550mm, and the colors are black,silver. 2.[Shock absorption] The upper part of the bicycle seatpost is equipped with a shock absorber spring with a distance of 55mm (2.17inch) to effectively reduce the strong impact received during bumps, allowing you to reduce the vibration on rough roads. 3.[Reversible, no need to remove the seat post]The head of the bicycle seat post can be directly opened. If you need to take out the items under the seat post, you can directly take it out without removing the seat post, which is convenient and time-saving. 4.[Size selection]The bicycle seatpost is suitable for the right size and bicycle model. You can directly look at the size on the original seatpost, or measure it with a toothpick, or directly ask the previous seller to determine the seatpost suitable for your model.