Quick view Douglas Products Douglas HTF Inhibited Propylene Glycol MSRP: $43.45 - $227.70 Douglas HTF Inhibited Propylene Glycol in 1 Gallon Containers Recommended for: Block Ice MachinesCirculating Beer SystemsClosed Water Loop Refrigeration SystemWood Boiler SystemClosed Loop... MSRP: $43.45 - $227.70 Quick Add Add to Wish list