The Triton 08417 shock is part of the Triton 08418 Center Prop Arm Assembly that is used on Triton 12-foot coverall snowmobile trailers. Center Prop Arms allow you to open the rear or the front of the coverall on all trailers, but they are required on all V-front models and/or trailers with 12' long beds. If you need to replace the whole assembly, not just the shock, you will need the Triton 08418 Center Prop Arm Assembly.