Safety Assurance - 100% OZONE FREE; ETL listed, FCC certified, CARB approved Smoke Eater & Odor Eliminator - Charcoal Foam Filter and Granular Activated Carbon Filter Bring 2x absorption for heavy smoke odor and other nasty smell. High Quality Personal HEPA Filter - Remove 99.9% of particles as small as 0.3 microns. Pre-filter and Mesh scaffoid are designed for supporting and prolong main filter's life. Compact But Powerful - 30 minutes to feel different in small room (size≤161 sq ft²/15 m²) when put on the desk and switch to speed Level 3. Fit for bedroom, office, dorm etc. Ensure Sound Sleep - Noise is merely 32dB at the lowest mode which will not affect you during work, study, sleep, meeting. No light design helps sleep in dark night.