Acoustic guitar tuner. The Rimpitch-C2 is a tuner that you attach to the inside of the guitar's sound hole. The tuner’s extremely slim and compact design allows it to be installed unobtrusively, and since the tuning meter is within your natural field of vision, you can glance casually at the tuning meter while you perform. It's an ideal choice for any acoustic guitarist who does not want to distract from their performance with a clip-on tuner. When tuning, the Rimpitch-C2 detects the sound through the vibration of the guitar itself. The body features a proprietary structure with a closely attached piezo pickup, allowing the sound to be detected rapidly and accurately. Features highly visible and readable LED display. Range (Sine Wave): E2 (82.41 Hz)–E7 (2637.02 Hz). Calibration Range: A = 438–445 Hz (1 Hz steps). Battery Life: Approximately 36 hours. Installable size: Circular sound hole of diameter 100 mm. Included Items: 1 x CR1620 lithium battery (3 V). Dimensions: 79 ✕ 32 ✕ 17 mm. Weight: 13g (including batteries). Colour: Black