Quick view Douglas Products Douglas HTF Inhibited Propylene Glycol MSRP: $117.43 - $615.39 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: $117.43 - $615.39 Quick Add Add to Wish list