AMPLOCK U-BRP2 boat trailer, trailer and RV coupler lock fits specific 2 inches coupler Molded to fit the specific shape of your boat trailer, trailer or Caravan (RV) 2 inches when unhitched; validate your measure and coupler with photos provided. Amplock offer the best protection specific to each trailer coupler size and type, if its not your trailer coupler on photos, go to www.amplock.com to choose yours and get the right Amplock trailer lock Easy to use with AMPLOCKs push and lock system The strongest lock to secure your boat trailer, trailer or caravan (RV) made with high quality materials and control and identification key system Materials used by AMPLOCK provide good rust resistance for use in all climates