Oil Lubricated Air Compressor draw air in with a pistion. For maximum efficiency, the pistion chamber needs adequate lubrication, for which oil is used. Portable oil lubricated air compressors are more durable.It is used for industrial purposes and long working hours. As they are well-lubricated, they run more quietly and longer life. It is idear for Spray Gun, impact wrench, Air Drill and Air Framing Nailer.They are best for use in homes and in shops.