Mobil Rarus™ 400 Series compressor oils are high performance ashless air compressor oils designed to meet the stringent requirements of leading compressor manufacturers. High quality mineral base oils and high performance oils are formulated to provide superior equipment protection and reliability for running compressors. in light and harsh conditions. Formulated with an additive system. These oils provide excellent wear protection and reduce maintenance costs by reducing equipment problems and minimizing deposit accumulation and transportation. Thanks to high FZG Ratings, the Mobil Rarus 400 Series is excellent. oils for compressor systems involving gears and bearings, crankcases and bearings. They are excellent choices as cylinder oils.