It's a helmet-mounted light, multipurpose, can be used in all types of ground operations. Provide flash or constant light. Powered by a standard lithium CR123A 3V disposable battery(battery does NOT included). photo cell for and extreme temperature operation. Waterproof and dustproof. With design of sliding switch, it not be inconvenient even when operating with gloves on or in the helmet. Positive visual and tactile confirmation of ON/OFF and operating status with no guesswork. Helps prevent inadvertent battery depletion if left ON in IR mode. model: Black bottom green light D size: 8.5x5.5x3.5cm Material: Nylon + electronic components colour: Gray Black Package Contents: 10 * Helmet light Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.