It shouldn’t be very difficult to find a nice lock for a hitch coupler but most locks try to be universal, fitting both a small 2″ ball and the commercial sized 2 5/16″ ball the Aerovault has. These multiple size locks are sloppy loose on a 2 5/16″ ball.
We’ve been looking for a while and recently MasterLock came out with this impressive lock specifically for a 2 5/16″ coupler. The set we’ve chosen also has a pin lock that goes through the locking mechanism on the coupler latch. Both locks are keyed the same.