CAS No: 3390-61-2 The vapor pressure and Diffusion Pump Oil IOTA 705 is a colorless transparent oily, single-component fluid designed for ultrahigh vacuum applications in the range of 5x(10-9~10-10) torr (untrapped). The vapor pressure and the best resistance to radiation. Silicone Diffusion Pump Oil IOTA 705-IOTA (phenylsilicone.com)