STP Ultra 5-in-1 Fuel System Cleaner and Fuel Stabilizer is scientifically engineered using advanced cleaning technology to keep all your engines running in top form. It contains 3X the amount of cleaning agents vs the leading premium gasoline to remove an average of 61%** of harmful intake valve deposits and restore an average of 95%*** of the original injector performance. This product also contains fuel stabilizer to help keep fuel fresh during storage. Compatible with gasoline engines (2&4 stroke), inclusive of boats, motorcycles, and lawnmowers. *One bottle contains 3X by weight the amount of cleaning agents compared to 20 gallons of the leading premium gasoline. **Average result of 6 modified ASTM D5500 and D6201 tests. ***Results based on ASTM D5598