This 400mm long seatpost will help you get a better ride height on a relatively low bicycle, and the head and seat angle can be adjusted for easy installation.Made of high-quality 6061 aluminum alloy, it has 4.9 super-high strength, maximum 580 pounds, so that it is light weight, never rust and never bend.It is suitable for most mountain bikes, road bikes, folding bikes, downhill bikes, track and field bikes, MTB, BMX, DH, etc.How to Choose a Size:Check the diameter of the original seatpost and choose the same size as the original diameter.Measure the inner diameter of the frame tube.Item Name: Bike Seat PostMaterial: Aluminum Alloy 6061-T6 01: 2.72cm x 40cm, 02: 3.09cm x 40cm, 03: 3.16cm x 40cmFeatures: Durable, Easy to Install, Bike PartsSuitable Frame Seat Post Hole Diameter: 27.2mm/1.07", 30.9mm/1.22", 31.9mm/1.24", Column Length: 400mm/15.75", Thickness: 2.5mm/0.10", Rear Position: 0 Degree/0mm (Approx.)Size:01: 2.72cm x 40cm/1.07" x 15.75" (Approx.)02: 3.09cm x 40cm/1.22" x 15.75" (Approx.)03: 3.16cm x 40cm/1.24" x 15.75" (Approx.)Notes:Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Please confirm the diameter of the seatpost of your bicycle before buying.Package Includes:1 x Bike Seat Post2 x Clip2 x Screw