Quick view Douglas Products Douglas HTF Inhibited Propylene Glycol MSRP: $36.22 - $189.80 Douglas HTF Inhibited Propylene Glycol in 1 Gallon Containers Recommended for: Block Ice MachinesCirculating Beer SystemsClosed Water Loop Refrigeration SystemWood Boiler SystemClosed Loop... MSRP: $36.22 - $189.80 Quick Add Add to Wish list