The snark is now ready to help you tune your instrument. As soon as you play a note, the Snark’s color display will indicate the note you are playing and how close to pitch you are. The left side of the display (red) indicates flat, the right of the display (yellow) indicates sharp.
If only red needles are lit, it means the not played is flat. If any yellow needles are lit, it means the note played is sharp.
You are in tune if the green needle and the green dot above it (at center of metal) are lit, but no yellow needles are lit
As the Snark is chromatic, you can easily deal with non-standard tunings. The Snark will read any note you play.