I bought this to be used on stage - the one thing it is, unfortunately, not suited for. The blue LED takes a lot of battery power, which wouldn't be a problem if you could use a 9V adapter. However, adapters cause a clicking so loud that the tuner cannot be used on stage (unless you turn the amp volume down). I should point out - the adapters I tested were an Ibanez and a Boss - which function with every other pedal I have.
It is now used to practice at home, which is a little disappointing.