UPANBIKE Bike Suspension Seatpost 400mm Length ?27.2mm 28.6mm 30.9mm 31.6mm Shock Absorber Seat Post for Mountain Bike Seat Post BMX Road Bike(31.6mm*Black+Red)

"?To Fit Frame Seatpost Hole:27.2mm;28.6mm;30.9mm;31.6mm(Pay Attention:please choose correct diameter size,different size is not compatible.). ?Extra Length:15.7""(400mm),help to raise height of saddle,so that tall rider don't have to bent much forward. ?Material:6061 T6 Aluminum alloy,high strength and light weight.CNC precise machining surface,non-slip and easier to lock tightly. ?Micro Adjustable Clamp:you can adjust the tilt angle of the saddle via the clamp to make the saddle horizontal.Double nails and double track design,adjust the angle of the cushion you need,to make riding more comfortable. ?Spring Coil Suspension:Build-in spring coil and damper rubber,effectively absorb the shock while riding,make your riding experience comfortable.Rebound force adjustable by tighten or loose the bottom nut.You can adjust the bottom nut to change the spring rebound force,to fit your weight and get best riding experience. Saddle clamp angle can adjust -5 degree to +18 degree."