Uses the same, proven bidirectional bacterial/viral filtration media used in the larger HEPA Light models, at half the size. High-level filtration protection while conserving patient exhaled heat and humidity. For use with adult and pediatric patients in anesthesia applications. Bacterial/Viral filtration efficiency: 99.9999+% True hydrophobic HEPA filter, HEPA Class 13. Smooth, lightweight, transparent, low-dead-space housing design for maximum patient and staff comfort.