Exhaust fragrances are a blast to use and will really give anyone riding near you a treat. A must for scooter rallies or that Sunday ride with friends. These Fragrances are intended to set you apart from the rest and sure to be a crowd pleaser. They do not enhance or inhibit performance and are safe to use in all internal combustion engines (2-stroke or 4-stroke). For best results use in vehicles without catalytic converters, but will still work either way. Treats up to 10 gallons.