The Time Atac pedals rely on two strong stainless steel spring traps to retain the cleats. The cleats that make up a pair with Time Atacs are different so that the amount of twist in the foot to break free of the pedal is different, depending on which shoes they are attached to. One way is easier for "beginners" because the twist required is not so much, the other way requires a fair degree of twist, and is designated for "experienced" riders.