These replacement sponge sticks are specifically designed for USB humidifiers, aroma diffusers, and mist makers. Made from high-quality absorbent sponge material, they effectively filter impurities and maintain optimal humidity levels for a more comfortable living environment. Each stick features a smooth cylindrical shape that fits most standard humidifier models. The sponge's porous structure traps dust and minerals while allowing water vapor to pass through freely, ensuring consistent mist output and longer appliance life. Available in multiple pack sizes to suit different replacement schedules. Simply remove the old sponge and insert a new one—no tools required. Regular replacement helps prevent mold growth and keeps your diffuser running efficiently.