* Sales of antifreeze fall outside of the prepaid freight programs on a company and or customer level and freight charges will be added to all orders. * Sold per gallon but must order in multiples of 6. Camco Boiler Antifreeze is a premium heat transfer fluid with special corrosion inhibitors. For use in traditional boilers and closed boiler and solar systems. Can be used with AquaHot system. Good to -100 degrees. 1 GALLON.