Seiko Keyring Tuner
Place a Seiko ST01 stick style chromatic tuner on your key ring, gig bag, backpack or bag and never be left out of tune! Not only is it small enough to fit easily in your pocket, the Seiko ST01 has an extremely simple interface. Just turn on the power switch, play a note and the built-in microphone will pick up the note being played. Use the LCD display to find the note input and whether it's sharp or flat. The ST01 is about the same size as a USB memory stick. It is powered by a CR1220 lithium battery (included). To preserve battery life, the Seiko ST01 tuner will automatically power down after 2 minutes of inactivity.
Other features of the Seiko ST01 tuner include: A4=440Hz Calibration A0 - C8 Tuning Range Auto Chromatic Tuning Mode