Multi-Mounts should be used when mounting on snowmobile tunnels that have heat exchangers directly under where the Q.R.S. is to be mounted (extending the mounting holes to the outside of the tunnel). Multi-Mounts should also be used when mounting on metal tube racks on ATV's. Instructions and hardware included. '08 Ski-Do REV-XP Multi-Mounts also available (Item # REV-XP multimounts)