7 Regenerative blowers, regenerative blower systems composed primarily of a motor, valves, belts, pulleys, piping, gauges and mounts, positive displacement blowers, positive displacement blower systems primarily of a motor, valves, belts, pulleys, piping, gauges and mounts, filters and housings therefor, vacuum pumps, air compressors, and valves, tubing, piping, stands, enclosures and silencers