Carlisle Ultimax 3 has evolved into Ultimax PRO. Thicker cross section so more surface area is in contact with clutch. New cog design dissipates heat and aids flexibility Runs cooler for better performance. Run cool, run long & run fast with Ultimax PROAdditonal Fitment:1996-1997 SKI DOO BRP MACH Z LT1995-1997 SKI DOO BRP MACH I1994-1997 SKI DOO BRP MACH Z1996-1997 SKI DOO BRP FORMULA III1995-1997 SKI DOO BRP SUMMIT 6701995-1995 SKI DOO BRP GRAND TOURING SE 6701996-1996 SKI DOO BRP GRAND TOURING SE1995-1996 SKI DOO BRP FORMULA SS1997-1997 SKI DOO BRP SUMMIT 5831997-1997 SKI DOO BRP MX Z 670