Zipp Service Course Sl, Seatpost, 25.4Mm, 400Mm, Offset: 0Mm, Black* Redesigned Service Course SL seatpost is a new carbon post from Zipp, specifically tuned to be more shock absorbing than the comfort seatposts on the market, while still passing strict internal MTB strength test. * UD carbon fiber post mated to a two bolt 7050 aluminum head for precise and secure saddle adjustments* Compatible with all rail types* 400mm length* 240g (0) 249g (20)