Color:PURPLE Designing the best coupler locks is not an easy task. We pride ourselves on producing a \"glove like\" fit coupler lock. Rest assured that Proven Industries trailer lock products will leave you with simply the best coupler lock on the market. In addition, no other trailer coupler locks can secure your safety chains. Model 2178 is our most popular trailer coupler lock because it fits the most amount of couplers on the market. From an \"A-frame\" welded-on trailer coupler, to a straight bolt-on style trailer coupler, Model 2178 fits them both and will provide the most secure trailer coupler lock available. Model 2178 may fit other trailer couplers not listed. Trailer coupler lock model 2178 may not fit all trailer couplers. Please look at trailer coupler lock index pictures above for coupler match. This style will allow you to secure most standard S-hook style safety chains in lock.. **PLEASE CONTACT SELLER PRIOR TO PURCHASE FOR QUESTIONS REGARDING FITMENT**