07-19 KTM 250SX: Polisport Chain Guide (BLACK) This is where it all began, 30 years ago - Polisport started building aftermarket parts so that everyone could enjoy their bikes without worry and with even better looks and improved performance. Performance plastics kick-started its success and are still the core of Polisport.Injection-molded polyurethane Chain Guide.Tougher than stock guide.Direct O.E.M. replacement.