Santovac 5 Polyphenyl Ether is a vacuum diffusion pump fluid which operates efficiently, economically and safely to produce ultra-high vacuums. Recommended for the cleanest high and ultra-high vacuum applications which get down to less than 10-9 mbar. Santovac 5 Diffusion Pump Oil has very low vapour pressure, very high thermal stability. It is chemically stable, non-corrosive, non-toxic and safe at normal operating temperatures. It has great lubricating qualities for various pumping systems. Santovac 5 is a very pure fluid and as a result vacuum chambers and components remain cleaner, therefore, this results in less system maintenance and downtime.