12 fl. oz.     354 ml Where To Buy! 50016 Single Bottle Select a linkFlex-a-lite Dealer NetworkPurchase On-LinePAR Locator 500166 12 Pack Select a linkFlex-a-lite Dealer NetworkPurchase On-LinePAR Locator FEATURES Prevent Scale and Blockage Reduce engine temperature by up to 20 F Extend the life of your cooling components Improve coolant contact with radiator fins Race track surface approved This formula now has 4 times the active ingredients compared to the product we were showing at the S.E.M.A. Show, and this bottle size is now 12oz. You still use only 1 bottle for a 4 gallon system if using anti-freeze. Use 2 bottles if you are not using anti-freeze (i.e. plain tap water). This formula also has a lower PH value (8.5) so it will not be harmfull to the aluminum in the system (several of our competitors formulas have PH values above 10!)