Viking Vault Mfg. Ironclad Trailer Hitch Security-  Coupler Lock . Orange Made in the USA 3/16" All welded steel. Bolt Cutter Proof. (1) Master Lock- Puck with 2 keys Orange Powder Coat Finish Will fit 2 5/16" Big Tex/ Demco EZ Coupler. The only way to open this system is with the key. Only power tools or a cutting torch have any chance against this lock.Note: shown in black on trailer. Coupler/Hitch not included