The device offers two projection modes that you can toggle with the A and B buttons.

• A mode shows dark veins on a white background.
  

• B mode shows green veins on a dark background.
  

The underlying vein image is the same in both modes, only the color scheme changes. Choose the option that gives you the best contrast for the patient and the room lighting. Many users prefer A mode in brighter rooms, and B mode in dimmer rooms, but it is personal preference. Since switching is a single button press, try both and use the one that looks clearest for you.