Blaylock Model TL-50: features a 3/4" heavy duty steel locking pin. Fits most gooseneck 2 5/16" ball size style couplers - Bulldog, T.E.M., TEMCO, Hammerblow/Cequent style couplers. Use: simply install the narrow end (looks like a goose`s neck) over the coupler bracket near the handle. Bring the wide opening of the TL-50 into position over the wide part of the coupler. Insert the pin into the hole that offers the tighter connection, then install your padlock. ***Padlock is not included*** See model TL-55 for RAM couplers.