Nu-Calgon naphthenic mineral oil is available in three grades: C-3s (150 SUS), C-4s (300 SUS) and C-5s (500 SUS). All viscosities are manufactured by Calumet Lubricant Co. and are approved by Copeland, Trane and other compressor manufacturers, approvals varying by viscosity. They are specifically designed for today s high performance air conditioning and refrigeration compressors. These modern compressors run at higher speeds and generate higher temperatures, and they need better lubrication. Use of C-3s, C-4s, and C-5s mineral oil will insure continued efficient system operation, providing the important properties required from a good refrigeration oil. Nu-Calgon mineral oils combine excellent solubility and stability with good floc and pour points to provide excellent low temperature performance.