1/2" & 5/8", Barbell Receiver Pin & Coupler Lock, Stainless Steel Sleeve Turns This Single Unit To Fit Both Receiver Sizes, Straight Barbell Style Pin Provides Function & Protection In 1 Unit, All Weather Cap Protects Key Way From The Harsh Elements, Coupler Pin & Lock Provides The Same Function & Protection With Keyed Alike Lock To Secure Your Trailer Coupler In The Locked Position, Coupler Latch (7/8" Width) Also Has Weather Proof Cap To Keep Keyway Safe From The Elements,K1 Key Way For Both Locks.