Boss TU-3S Chromatic TunerThe BOSS TU 3S Chromatic Tuner provides the same function, accuracy, and display, as the TU 3a go to stompbox tuner for many electric guitarists. However, this model doesn't sport a muting footswitch; it's always on. This feature, in addition to its small size, renders it suitable for integration in any pedalboard or stompbox rig in which space saving is paramount. It features tuning modes for six and seven string guitars, bass and six string bass