ACPL-VCP DC is a single-component silicone oil specially designed for use in ultra-high vacuum diffusion pumps. It has high thermal oxidation stability, small viscosity-temperature coefficient, narrow boiling point range, and steep vapor pressure curve (a little temperature change, a large vapor pressure change), low steam pressure at room temperature, low freezing point, coupled with chemical inertness, non-toxic, odorless, and non-corrosive.