EXAIR's compressed air operated Heavy Duty HEPA Vac attaches to an ordinary 30, 55, or 110 gallon open top drum to turn it into a powerful, HEPA (High Efficiency Particulate Air) quality, industrial vacuum cleaner. Like the Heavy Duty Dry Vac, it's powerfully designed to move more material with less wear. Engineered for dusty environments that require regular cleaning, the HEPA filter is designed with high capacity in mind. Ordinary vacuums can clog up quickly in environments with an abundance of dust or particulates. An economical, easily maintained pre-filter stops larger particles of debris while the HEPA filter handles smaller matter. The Heavy Duty HEPA Vac does not use electricity and has no moving parts, assuring maintenance free operation. The Heavy Duty HEPA Vac's lever lock drum lid fits any open top 30, 55 or 110 gallon drum. Moving it from one drum to another quickly, making it easy to keep different materials separate for recycling. www.exair.com/184/hepa.dirpr.htm