Designed specifically for acoustic guitar, ukulele, and other acoustic instruments, the chromatic NS Micro Sound hole Tuner remains perfectly concealed within the instrument s sound hole for discreet tuning. The non-marring universal mounting clip allows stress-free installation, while the highly sensitive piezo transducer senses vibrations directly from the soundboard for fast and accurate tuning response. The bright, multi-color display allows easy viewing in any environment. It s so small, convenient, and accurate, you ll want one for every acoustic instrument you own! D Addario electronic tuners are designed by musicians for musicians featuring intuitive features, easy to read display's, and exceptional tuning accuracy.