NEW T3.6 Air SP Carbon SoleR is SPEEDPLAY APPROVED for superior power transfer, 4 mm reduced stack height, 62 gram lighter installed weight, 6mm of additional aft adjustment and simplified set up.Vent Carbon Sole: Super stiff with openclose vents for 4 season comfort. Sole vents help drain water after wet transitions.Triathlon specific upper has a plush, brushed interior with minimal seams for sock free comfort. Notched top strap opens away from the drive train. Large heel loop for fast transitions. SIDI Heel Cup. Replaceable heel pad.