This is a small clip-on tuner from Crafter. It has an advanced vibration sensing tuning system, and a condensor microphone built in. The tuner clips directly onto the headstock of any guitar and uses the vibrations to give you highly accurate tuning. No leads required at all. You can tune electric, acoustic and Bass guitars with this superb tuner, in fact just about any instrument with strings! It has a handy built in power-off, so you don't end up with a flat battery when you need it the most! The tuner has an ultra sharp back-lit screen for ease of use on a dark stage. The tuner background changes to Green when the string is in tune, so you can see at a glance when you are ready to play.