Oarlock Pin (set of two). 1/2" Oarlock pin with clamp and retainer ring. Fits standard oar lock receivers and sockets. Retainer ring keeps oars from coming out of oarlock. Specifically designed for thin shaft oars. Made of saltwater resistant galvanized steel. Retainer ring is stainless steel. Fits 1.25" - 1.5" shaft diameter oars. Oarlock pin diameter is ½” (0.47 - 0.48”) or 12mm. Overall dimension including clamp is 5.5" long by 1.5" wide, and weighs 7.6 oz.