The ML-21 mic light is brighter than ML-8, coloured NVIS Green A, and is compatible with all night vision goggles and devices. The generation III mic light employs three LEDs with a push on/push off switch that can be actuated by the lip or tongue. A slight push on the switch triggers a momentary light, while a further push will switch the light on until pushed again. The ML-21 is excellent at preserving dark adaptation--powered by two AA batteries (not included).