It's on a single axle international truck with a factory made dump box. I'm wanting to pull my gooseneck trailer off the rails of box since the box tips to far over the back to use frame rails, therefore need to be able to lock bed to frame. Looking for something automatic I can put on that will activate,deactivate by air, like when I engage,disengage the air pto. So it's a no brainier for anyone that may get into truck.