Strobe Mode - the note played lights up in green.Red LEDs chase around the rotary display. As you tune, they slow down. When the red LEDs stop spinning, you are in tune. Sweep Mode – the note played lights up in green. A red LED will appear to the left of the green LED if flat; to the right if sharp. When only the green LED is lit, you’re in tune. Tuner may be calibrated from A435-A445 | Multi-tool features: winder, cutter, string stretcher, and bridge pin puller. Runs on one CR2032 lithium battery (included) |