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.