Patent pending design, the BT3 coupler lock is designed primarily for the Forged Iron Collar-Lock style couplers sold under Bulldog and Fulton brands.  Fits 2 5/16" size ball couplers.  Limited Lifetime Guarantee on defects in material and/or workmanship.
 
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.