5/8", Barbell Receiver Pin & Coupler Lock, Stainless Steel Sleeve, 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, Uses Master Lock Key Blank K1BOX Or Ilco Blank M1 TV #320-952.