1UP XTREME DUTY ADD-ONCapable of hauling up to an additional 120 lbs, the Xtreme Duty Add on increases the capacity of your 2" Xtreme Duty Rack by one bike spot. Features Easily mounts to XD Rack (not compatible with other racks) Xtreme Duty Wheel Chock* (sold separately) reduces steer tube rotation minimizing bike movement Total carrying capacity: First XD Add On: 120 lbs. (Remove the battery in order to stay within the rated capacity) Road rating: See bike racks Vehicle