EASY TO FILL 150ML TANK - It couldn't be any easier - simply unscrew the top and fill it with water. The water tank holds 150 mL of water. Do not add distilled water or essential oils to the small cool humidifier. The window in the water reservoir shows when the level is low. AUTO SHUT-OFF - A built-in auto shut-off feature means less effort and planning on your part. The built-in water sensor automatically turns off power when water falls below adequate supply. The leak-proof design keeps the surrounding area clean and dry. COLOR NIGHT LIGHT - Add a colorful mood and ambiance to the room with soft glow night lighting. Colorful light transitions through 7 different colors while on. Optional single button On/Off control. To turn on, press and hold the button, To turn off, repeat the process.