Enclosed Enclosure Tankmount Oil-Less Scroll Compressors Have No Oil Contamination Of End Product For Optimum Performance. Enclosed Enclosure Tankmount Oil-Less Scroll Compressors have fewer moving parts to provide long lasting durability. Compressors are ISO 8573-1 Class Zero Oil-Free Air to provide low noise and vibration. Oil-less operation provides low maintenance with no oil changes needed and less filtration required. Sound enclosure cabinet reduces sound to 51 dBA so it can be installed near point of use. HPs are 3 and 5. Voltages are 208, 230, 208-230 and 460. 1 or 3 phase motors. Tank orientation is horizontal. CFM and PSI vary per model.