It seems to function first for the sound and then the light since when I hit the button, it immediately begins to dim. However, it could be that I have the burner in the incorrect position because when I press the button, there is no arc but the mask is still dim, and I need to wait till it brightens up before I can use it. I'm not sure whether this is a flaw or a benefit, but I didn't manage to bag even a single rabbit during my hunt.