Only Adjustable Humidifier for Musical Instruments Plus Hygrometer (Purple / Silver) By HUMISTAT USA Avoid costly repairs due to warping, shrinkage, peeling, splitting, cracking and checking The only adjustable instrument humidifiers sold anywhere Easily refillable. You can see the water level and know precisely when to add more Eliminate all guesswork with a HUMISTAT "Combo" -- a hygrometer to show you the humidity level and a humidifier you can adjust to the setting you want Top-quality materials, yet affordably priced