Quick view Douglas Products Douglas HTF Inhibited Propylene Glycol MSRP: $4,425 - $23,191 Douglas HTF Inhibited Propylene Glycol in 1 Gallon Containers Recommended for: Block Ice Machines Circulating Beer Systems Closed Water Loop Refrigeration System Wood Boiler System Closed... MSRP: $4,425 - $23,191 Quick Add Add to Wish list