Ritchey Comp Zero Carbon Seatpost: 27.2mm 400mm BlackRitchey Comp Zero Carbon Seatpost: 27. 2mm 400mm Black. The Ritchey Comp Zero Carbon post offers no slip saddle engagement and high adjustability by securing the rails with fore and aft bolts. Whether youre hitting rough singletrack or remounting in a hurry this ensures the saddle stays exactly where you want it. TECH SPECS Length 400 Color Black Diameter 27. 2 Material Carbon Defined Color Black Clamp Style Standard Rails Offset (mm) 0