Quick view Douglas Products Douglas HTF Inhibited Propylene Glycol MSRP: $87.78 - $460.00 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: $87.78 - $460.00 Quick Add Add to Wish list