We use use a bacterial filter that is manufactured by Microgard. It is designed to capture 99% of all aerosolized bacterial and viral pathogens. It is the same type of filter used in hospitals by respiratory technicians. This filter is used with the Go Direct® Spirometer (GDX-SPR) and the Spirometer (SPR-BTA)

The PDF below is the specifications sheet released by Microgard for this filter.

http://www2.vernier.com/til/1532/MicroGard.pdf

RELATED VERNIER PRODUCTS
Disposable Bacterial Filters for Spirometer (SPR-FIL10) (pkg. of 10)
Disposable Mouthpieces for Spirometer (SPR-MP30) (pkg. of 30)
Noseclips for Spirometer (SPR-NOSE10) (pkg. of 10)
Spirometer Flow Head (SPR-FLOW)