This oil will allow you to keep only one oil in stock for all of your OEM and retrofit needs. With this oil and Mineral oil for R12, you are stocked with premium oils for every job you tackle. The double end-capped chemistry makes this oil resistant to moisture. The Karl Fisher laboratory tests that we ran show that the absorbtion is far less than normal PAGs and esters. We kept one bottle with the factory seal and opened another and left it open for 24 hours in the warehouse with the evaporative coolers on. For those in states that never used them, they will add moisture into the air. The results were that the opened bottle had almost the exact low moisture level as the one that was sealed.