Reese Towpower 70305 Professional Chrome Coupler Lock Coupler lock has a 1/4 inch pin with a 5/8 inch span Chrome plated steel construction with rubber cap includes dust cover and o-rings for ultimate weather resistance The square key design offers the ultimate theft protection with thousands of key codes and is virtually impossible to pick Patented ball bearing locking system eliminates weak point Reese Towpower Professional lock have a limited one year warranty