Size specific pro-level concave platform pedal provides optimal shoe/pedal interface.-Optimal surface area-Minimal profile 11mm-13mm thin-Concave platform for secure foothold-10 adjustable pins per side for grip-Premium bearings & seal system-Grease port for easy maintenance -Stamp small recommended for shoe sizes: 5-10 (us) // 37-43 (eu)-Stamp large recommended for shoe sizes: 10-15 (us) // 43-49 (eu)