The Blaylock TL-22 Total Encasement Bulldog Coupler Lock is intended for recreational and industrial use. It fully encases 2" Bulldog style couplers. Compatible brands include Hammerblow, Cequent and Bulldog couplers. The solid cast aluminum construction completely encases the receiver. Hardened solid steel pin securely fastens the lock over the coupler. High grade aircraft aluminum provides security.