Shimano make makes a system known as SPD, it is a design of clipless bicycle pedals used for Mtn Bikes. Shimano also makes a number of different SPD cleats and clipless Pedals. An important distinction between black "single release" cleats (SM-SH51) and silver "multi release" cleats (SM-SH56). Shimano also makes a system known as SPD-SL used for Road Bikes. All pedals come in a variety of alloy and carbon composite materials desgined for world-class roadies.