The SDI Diagnostics PulmoGuard S™ PFT Filters are high-efficiency, single-use barrier components engineered to capture aerosol contaminants during pulmonary function testing (PFT). Designed specifically by SDI Diagnostics for exceptional clinical cross-contamination protection, the PulmoGuard S™ series features a custom structural profile engineered to fit Vyaire / CareFusion / Sensormedics Vmax® spirometers natively without requiring a separate plastic adapter ring.