Zipp Service Course SL Seatpost 31.6mm 400mm Offset: 20mm BlackSpecifically tuned to be more shock absorbing than the comfort seatposts on the market, while still passing our strict internal MTB strength test. Flex engineered into the light weight carbon tube keeps the rider comfortable over any terrain. Secure, two bolt clamp makes for easy micro adjustments of saddle position, and the head has been redesigned for maximum bolt head accessibility. Clamp works with all saddle rail types. SRAM Model ID: SP SC SL C2