VR-12 - Radiator Cooling System Protection &ndash; 6 pack 1 bottle treats up to 3 gallons of any fluids. Compatible with all vehicle's coolants - Antifreeze energizer and cooling system booster. Improves gas mileage and extends the life of your vehicle. Organic & Biodegradable, Improve heat transfer, lowers temperature. Recommended maintenance: use 1 bottle every 12,000 miles or every 5 months.