This is for a never used Peterson Strobo-Clip tuner that fits on the headstock of your guitar, banjo, whatever, and that is like a portable strobe tuner but small. I got this but ended up using a tuner that fits on the hooks of my banjo. Box, instructions & tuner but battery not included. It takes a 2032 battery which you can get at any drug store, Amazon, etc. Thanks for looking...