Safeguard your instrument. Shar Music® created the Humidi-Guard™ to be easy-to-use, inexpensive, and effective. Changes in humidity can wreck your instrument. Solve the problem with ease: soak the Humidi-Guard in water and slip the flexible tube through the F-hole of your bass. Done and done!

(And a note for bass owners: the Humidi-Guard may not fit through all bass F-holes  – the tube is 15.5 mm at its widest point; you may want to measure the F-hole before you buy.)