Info from Manufacturer: The huge success of our original blue Oasis® "sound-hole" Guitar Humidifier brought numerous inquiries about how to provide humidification for other wooden instruments such as violins, violas, cellos, mandolins, jazz guitars, guitars with flat top cases, and some woodwind instruments like clarinets. After careful consideration and research, we developed our Oasis® Case Humidifier. This style of Oasis® humidifier attaches to the inside of your instrument case. It gives you the same reliability and ease of use as our original humidifier, outperforming other case and instrument humidifiers by doing the following: Making it easy to see when it?s time to refill. Providing long-lasting humidification. Ensuring no leakage due to overfilling. Promising two levels of leak protection. How does it work? A neodymium magnet* in the humidifier enables you securely attach it inside your case, while still being able to easily remove and re-attach it to either a steel belt-style clip or a stainless steel strip with adhesive backing (both are provided with the humidifier). The belt-style clip fits over the side of your case, providing a flat vertical surface to which the magnet can adhere. The adhesive-backed stainless steel strip allows for either vertical or horizontal attachment anywhere there is a flat surface inside the case.** This type of humidifier provides the flexibility to position the humidifier in a wide variety of locations within your instrument case. A 10cc. syringe comes with the humidifier increasing your control while filling and refilling. Since the Oasis® Case Humidifier holds about 32cc?s of water, it will take 3+ syringes of water to fill the first time. After that, refills should only take 1+ syringe of water. Because tap and bottled water contain dissolved minerals that can clog the liner, distilled water is recommended to extend the useful life of your humidifier.