The Cotter Pin Control Arm is a metal fastener with a circular head and two prongs or legs. To use, insert cotter pin into a drilled hole to secure bearings until the head is snug with the bearing. Bend the legs or tines outward in opposite directions to secure. Compatible with RY10MA and RY10MA-PRO Melter Applicators. Check your machine for the correct part number and location of this fastener item.