A movable ring allows the magnet to be rotated 360 degrees. This allows you attach the unit not only to left-handed guitars, but also to any metallic portion of your guitar, so you can tune with the conveniently at any angle.
An LED indicates the string number that’s closest to the string you play, letting you know at a glance which string is being tuned. When you’ve reached the precise pitch, the upper and lower LEDs will both illuminate. The upper LED blinks if you’re sharp, and the lower LED blinks if you’re flat. The LED will blink more rapidly as the string gets farther from the correct pitch, and will slow down as you approach the correct pitch.