Univerzal Transducer for Guitar, Mandolin, Violin and Other Instruments. The Shadow SH 711 is a fast and easy-to-install disc transducer designed for any instrument. The larger 20mm transducer senses more low frequencies than smaller 12mm transducers. Requires no battery and installs in seconds. Sensor mounts to any instrument to sense vibrations and convert them to an electrical signal. Sensor adheres with included non-permanent ''tak'' adhesive. Includes 30 cm cable with 6,3 mm Output Jack.