Boston BTU-205 is a multi-functional chromatic guitar/bass/violin/ukulele tuner that can be used to tune a wide range of stringed instruments, including guitars, basses, violins, and ukuleles.

The tuner features a large, backlit LCD display with easy-to-read note and string number indicators, clear note accuracy indication, and a tuning mode indicator. This makes it easy to see what note you're playing and how close you are to being in tune.

The tuner uses a high-sensitivity microphone to detect the pitch of the string being played and provides accurate tuning within a tolerance of +/-1 cent. It also features an A4 calibration function that allows you to adjust the pitch reference to match your instrument's specific tuning needs.