Ad a little more Metal to the rear tunnel of your snowmobile. The CFR XP/XM/Gen 4 Blades are designed to be fastened to the outside or inside rear tunnel of your Ski Doo snowmobile. Blades ad 50% more strength to the rear tunnel. The XP/XM/Gen 4 Blades are recommended if you travel on bumpy roads carrying lots of extra weight on the rear tunnel of your snowmobile. Blades also available for Arctic Cat M series 2005-2008 and Yamaha Nytros as well. Features: -Anatomically designed to fit the rear tunnel -Blades all come in anodized black. -Come complete with 1 right/1 left side and with stainless steel rivets. Made in Canada.