Pearl Izumi Men's Tri Fly Octane II Cycling Shoe 100% Synthetic Imported Synthetic sole 1:1 anatomic tri closure: eliminates hot spots and removes pressure from your forefoot (patent pending) With 9mm second skin upper: the thinnest upper on the market, it adapts comfortably to your unique foot shape to eliminate hot spots and offers superior breathability Minimally constructed for barefoot comfort. Octane sl insole provides unheard of lightweight and support Octane 1:1 power plate: octane grade uni-directional carbon for feather-light stiffness; direct-vent technology for cooling and drainage Concave shaping for ultra low 6.5 millimeter stack height, enhanced plate stiffness and anatomic support