OCTANE SL III RD 100% Synthetic and fabric Synthetic sole ALL NEW OCTANE 1:1 Power Plate: Octaine Grade Uni-Directional Carbon for feather-light stiffness; Direct-Vent technology for cooling and drainage; concave shaping for ultra low 6.5 mm stack height, enhanced plate stiffness and anatomic support. 1:1 Anatomic Closure: follows the natural anatomic shape of the foot to eliminate hot spots and pressure points. Octane SL Insole: provides unheard of light weight support. Pearl Izumi one-piece Clarino Rovenica upper with Direct-Vent Technology provides a second skin fit, minimum weight and maximum breathability.