Ski-Doo Heavy-Duty Rear Bumper-REV-XP/REV-XM 174" Recommended to reinforce tunnel when carrying more than one item on the tunnel, i.e. fuel caddy and a storage bag. Also reinforces tunnel when lifting sled using rear bumper. Heavy duty aluminum bumper for hitch applications. Designed in conjunction with the chassis, no sled modifications required. Compatible with REV-XM