Universal Coupler Lock:
Fits 1 7/8", 2", and most 2 5/16" couplers
 
Swivel Head Receiver Lock:
Fits both 5/8" and 1/2" diameter receiver holes
 
Adjustable Coupler Latch Lock:
6 locking positions from 9/16" to 2 3/4". Fits most couplers.
 
Keyed the same