Dow Corning® 704 is a single-component fluid for high vacuums of 10-6 to 10-8 torr (untrapped) and 10-10 to 10-11 torr (trapped). It performs well in tough, rugged applications and offers quick pumpdown, even after exposure to air at operating temperatures. DC 704 Diffusion Pump Oil is silicone based fluid with quick pumpdown cycles. It has thermal stability and is resistant to oxidation. Superior vapour pressure capabilities.