I put one on my bass recently. At home, it's quick and accurate, but on stage last night, I was having trouble getting a reading when going from E to drop D. It was "flat lining", like it wasn't picking up a clear enough vibration. I'm not sure if the ambient noise was effecting it or what. I'll keep it on for the next show and see if it was an annamoly, but today it's fine again at home. If you buy, the best price I've seen is Amazon. 2 PAC for $27.50.