Note: The diameter number is for frame seatpost hole, the seatpost measures a little smaller than the diameter number marked on the seatpost. e.g.: a 25.4mm seatpost measures about 25.0mm~25.2mm only, not exactly 25.4mm.</br> Replacement Seatpost, extended extra long length.</br> Material : 6061 T6 Aluminum </br> Length: 450mm</br> Tube Outter diameter: 25.4mm, 27.2mm,28.6mm,30.4mm,30.8mm,31.6mm</br> Package includes: 1 seatpost