This lock is ideal for securing unattended trailers. The lock comprises of a 16mm hardened shackle and 7 cut high security radial pin tumbler key lock. This lock works on Brian James, Ifor Williams and many more brands. The lock is easy to install, you simply slide the ball into the coupling on the trailer and push the ratched hardened steel shackle down tightly. Turn the key to lock it in place, for extra security you may also anchor the unit with a chain or cable.