Our Cr racing 2020-21 Skidoo G4 850 Expert Tunnel stiffener/Rear Bumper Kits have been redesigned by OEM by making the tunnels shorter! "Expert Models Only" .We designed our bumper to help strengthen the stock tunnel for purposes such as hauling extra fuel/gear ,Towing or repairing a damaged tunnel .We have tested these bumpers and proven there durability by towing other machines out of some of the nastiest non-groomed trails with no issues .The side plates and bumper  comes with all necessary predrilled holes making it a super easy installation.We recommend using an Air Riveter and allowing approximately 45 minutes to install.We also offer Custom colors for an additional fee so please email or call for more details.These bumper kits do not interfere with the factory removable Q-Link snow flap.