Used for more than 25 years in the manufacturing process, the sterile air filter cartridge has been tested for integrity through industry-recognized aerosol challenges. This test method involves challenging filter elements that contain clumps of virus - and bacteria-sized particles in concentrations at least 10,000 times the normal concentration in compressed air. Sophisticated instrumentation and a trained engineering team ensure that only cartridges that retain 100% of the viral and bacterio-sized test aerosols are transferred from production to packaging and shipping.