Fits 2 5/16" ball size with overall flange width of 4 1/4" or less.  Coupler lock includes a Master Lock padlock and two keys.   Lifetime warranty against defects in material and/or workmanship on housing, Master Lock standard warranty on padlock.
 
All locks can be keyed alike.  If you buy multiple locks and want them keyed alike please add a note to your order.  I will contact you for details.