Gemini xera light head lightthe gemini xera light is a powerful lightweight versatile and affordable head light with an output of 850 lumens you can be sure the xera leds will brighten your path the top of the line cree xm l emitter is currently the top contender for maximum efficiency and brightness delivered in a small package this xera light weighs just 52g but its still extremely powerful the lumens are measured in an integrating sphere the complete system can be carried on the head