Fit over the end of the quick release ball lock pin and allow the pins to be used in applications where the receiving hole is not within tolerance or is out of round. Fit over the end of the quick release ball lock pin and allow the pins to be used in applications where the receiving hole is not within tolerance or is out of round. The receiver caps can replace cotter pins and hitch pins to allow you to take advantage of quick changing and fieldwork without tools. The caps are made from 300 series stainless steel. The Grip Length Reduction is the amount of pin that is inside the end cap which reduces the useable length of the pin by this amount.