Wide applicability: This humidifier cleaning box is compatible with for ProTec PC-1 and PC-2, and is suitable for most evaporators, steam generators, ultrasonic humidifiers, steam steamers, gentle humidifiers and fish tanks. Excellent working performance: These humidifier cleaning balls can keep the of the humidifier clean and work normally. Keep the humidifier water tank and fish tank clean. Extend the service life of the humidifier and save cleaning time. Keep it clean for 30 to 60 days. Easy to use: Just put the humidifier cleaning box into the water tank and start working. A cleaning ball can be used for the humidifier, and the water tank capacity does not exceed 1 gallon. For humidifiers with a capacity of 1 to 2 gallons, it is recommended to use two cleaning balls. We recommend replacing it every 30 to 60 days. Reminder: The size of our humidifier cleaning ball is 2.36x1.18 inches/6x3cm. The filling can be used up to 40 times. The diameter of the humidifier opening should be at least 1.18 inches (approximately 3.0 cm). Please check your humidifier opening to make sure it is large enough to accommodate these humidifier cleaning boxes. Excellent Performance: The active ingredient of the humidifier cleaner is mainly silver ion. Humidifier cleaner fish can extend humidifier wicking filter life and keep the water clean, prevent objectionable odors and reduce the number of cleanings. colour: blue Material: plastic Package Contents: 10 x Humidifier water tank cleaner ball Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.