Mcgard Outboard Lock 50Hp Yam UpDesigned to lock the outboard onto the transom, simply replace one of the mounting nuts with a McGard locking nut. A free spinning collar turns if attacked by gripping tools, protecting against theft and inconvenience. (74049 fits most of the motors listed and will fit other small outboards with a 5 16" hole in the transom bracket for mounting the motor.) Description : M12 x 1. 25 Yamaha 40+ hp (2 stroke), 30+ hp (4 stroke), Honda 40+ hp, Suzuki 25