ACC-FUELM-RX-04 Yamaha Fuel Med Rx. Designed for continuous use. Treats 5 gallons of gasoline. Our special formulation stabilizes all types of gasoline. An alcohol-free formula that not only locks in fuel potency but helps to prevent fuel oxidation, phase separation, gum and varnish build up. Good practice is to treat the un-used fuel no later than 7 days after purchase. Best practice is to treat fuel at time of purchase.