The SDI Diagnostics PulmoGuard II PFT Filters with 1-Inch Outer Diameter (O.D.) Mouthpiece are high-efficiency, single-use barrier components engineered to capture aerosol contaminants during pulmonary function testing (PFT). Designed by SDI Diagnostics to eliminate cross-contamination risks, this specific configuration features a tailored 1-inch O.D. integration port, allowing it to connect natively to compatible spirometers without demanding an extra plastic adapter ring.