RIX Ships Microboost Compressors for Oxygen Cylinder Filling. Finishing its development program, RIX has launched the industry’s first electric-motor-driven compressor for very small cylinder fill requirements. The MicroBoost uses three stages of oil-free compression to go to 2,200 psig (150 barg) and is used to fill oxygen or nitrogen cylinders. With a with a ß HP motor, the MicroBoost is the smallest cylinder filling compressor in RIX’s extensive high-pressure compressor line.