This is the spring-loaded safety lock for bodygripping traps made by RAM in Canada. It works on all sizes of body grip traps and is very easy to position over the top of the traps jaws. When the trap is placed in position, the last thing you do is to compress the spring of the safety device and remove off the top of the trap. Your hands are never in danger of the trap inadvertently closing on them. A safety device is STRONGLY recommended for anyone handling bodygrip traps, especially the larger sizes, i.e. #280 or #330.