Excellent. Does exactly what it says. It's the best Bass tuner I've ever used. I've had other tuners, some of which can't even register notes low enough to tune a bass, and some that claimed to be bass tuners but were always a little bit off, or overloaded with ads. This has a very small, non intrusive banner ad in the free version, and the remove ads cost was 19 Australian cents, which I was happy to pay. This is how ad supported/free apps should be made. This dev is great and I've ended up with their chord chart app and guitar tuner app as well. Get this though.