Clamcleat rope cleats . The principle of the converging tapered grooves ensures grip without wear. Simply lay the rope which will automatically cleat under load. To release just jerk upwards. The nylon models remain best value for where high loads or rope surge are not encountered. With the advent of smaller and harder core rope diameters and burn, the higher load demands the aluminum "racing" equivelents which are now becoming the norm. For rope sizes 5/16" to 1/2".