INSIGHT SEAT POST EXTENDERThe seat post extender is made for racers when you need to warm up or cool down after a race, or for when you want a more comfortable sitting position when crusing around, due to the ultra low frame designs and super short race seat posts. You just insert your current seat post and seat into the extender and ride away. Sizes Lengths : 22. 2 x 360mm uses 25. 4 seat clamp25. 4 x 420mm uses 31. 8 seat clamp27. 2 x 420mm uses 31. 8 seat clamp Requires an