Cotton Stick Replacement Filter Compatible for 4 in 1 Hydro Mist USB Portable Personal Humidifier For the Cotton Stick: Product size: 7mm*90mm Features: Regular appearance, full, white color Good elasticity Uniform porosity distribution Absorbent is strong Water storage large Volatile stability Non-water soluble Non-clogging, keeping the volatilization speed of Aqua consistent. Please soak filter stick prior to installation Filter can be cut for length to fit other portable humidifiers Package contents: 1 Pack 15 cotton filter sticks