Fit For Most Humidifiers: This demineralization cartridge is compatible with 0.5-gallon ultrasonic humidifiers including UHE-CM65, UHE-WM70, UHE-OC1, UHE-HDC4, UHE-CM45B, UHE-CM25, UHE-WM16, UHE-OW14, UHE-WM85. It is also suitable for evaporative, cool mist, and warm mist humidifiers. Easy to Use: Simply drop the cartridge into the water tank for fresh, clean mist. Replace every 30 days. This humidifier cleaning cartridge contains no harsh chemicals. Eliminates Mineral Build-up: Helps prevent and reduce white dust caused by minerals in hard water, such as calcium and magnesium. Note: The humidifier's opening diameter should be at least 0.9 inches (approximately 2.3 cm). Please verify that your humidifier opening is large enough to accommodate the cartridge. Purifies Water: Reduces up to 99% of odor-causing substances and inhibits the growth of harmful contaminants. Helps keep mist clean and reduces the frequency of tank cleaning. Size: 4.6 x 2.3 cm (1.8 x 0.9 in) Color: Blue Material: Plastic Package Contents: 20 x Humidifier Tank Cleaning Cartridges. Note: Lighting and monitor settings may cause slight color variations between the image and the actual item. Measurement may vary by +/- 1-3 cm.