2001 Polaris Indy Sport Touring 550 ES - -. 1999-2002 Polaris RMK 550 Trail - -. 1999-2002 Polaris Indy 550 RMK Trail - -. 1999-2001 Polaris Indy 550 Super Sport - -. Engineered to provide the best possible path for combustion chamber heat transfer to cylinder walls.