OxiClear N99 Refill Filters, Activated Carbon Filter (Pack of 10)ULTIMATE FILTRATION POWER Premium OxiClear N99 filters with advanced activated carbon trap 99% of pollutants including PM2. 5, smoke, bacteria, viruses, allergens, and odors. Clean breathing, every time. EASY REPLACEMENT & LONG LASTING Replace every 100 hours (~1 2 weeks daily use) to ensure peak filtration. Keep it fresh, keep it safe. ADVANCED CARBON TECHNOLOGY Our activated carbon layers expertly capture harmful gases like nitrogen dioxide, sulfur