The clip-on D’Addario Eclipse Tuner provides unparalleled performance, pairing beautifully with lower-stringed instruments for fast, accurate chromatic tuning. The Eclipse Tuner's multi-swivel action allows for the perfect viewing angle when used with cello and double bass, featuring a full-color vertical display, auto power-off, and pitch calibration––all in a discreet, compact design. Note: For optimum accuracy, attach the tuner to the lower-strings side of the bridge while in use. CR2032 battery included