The all-new design “5 in 1” WMT-565C String Instrument Mate features metronome, tuner, sound, hygrometer and thermometer, which is useful for various  musicians.  To maintain their instruments, musicians need to be aware of the humidity and temperature of the environment. Acoustic instruments, in particular, are very sensitive to humidity levels. With Hygrometer & Thernmometer equipped, you can easily check the humidity and temperature of the environment and protect your instruments.