The dramatically designed DT-4 has a unique circular pitch indicator that lights up to let you know when you're in tune. Plus, with the DT-4's large LED readout, you can tell right away the note name of the pitch you're tuning. The DT-4 also uses red tuning guides to help you hit your pitch dead on. This instantaneously visible readout is housed in a compact, cool-looking design that can go anywhere. The DT-4 offers super-precise tuning over a note range of A0 (27.50 Hz) to C8 (4186.01 Hz). Plus, you can adjust the calibration of the reference pitch in 1 Hz steps in a range of 410 Hz to 480 Hz.