This is the ultimate lock to secure your Trailer/Caravan/Jet Ski etc. when left unattended. It consists of a massive, heavily built cast stainless steel frame with a security crossbar that is almost impossible to drill or cut through - even with an angle grinder! It is not only secure but it has a tamper alarm with a +120dB siren! The siren electronics is absolutely water resistant and comes with a CR123A long life battery (Spare batteries available). It comes with 3 x security keys that must be reordered from the factory if needed. Will work with or without the dummy towball and fits non-towball trailer hitches as well, including DO35 and Treg couplings.