Some 2009 Arctic Cat two-stroke models have the electronic reverse system and require a notch in the ramp for the reverse. These are still the earlier style adjustable "C" helix models that require a DHC-100 cover kit or an `05 type Arctic adjustable cover and hardware to use on the newer sleds that came with a cast one-piece helix.
Dalton designates all models with the notch for electronic reverse system "CR," followed by the angle. If it is a progressive type cut it would be designated by the suffix "P" after the part number.
Contact Dalton Industries (902)-897-3333 or www.daltonindustries.com.