The HYGIENO FILTER's provides high-efficiency ASHRAE air filtration performance in a compact, supported media design. The Rigid Cell Filters are designed for use as secondary filters in areas such as a Pharmaceuticals, Laboratories, Hospitals or as Pre-Filter to HEPA filters. The full surface area of the filter media is always available, even after prolonged use and heavy dust loading. The media is housed in a rigid frame with an optional header, providing a sturdy construction that is easy to install in front, rear or side access systems.