Measures 2 1/2" overall. Black composition housing. Three LEDs produce up to 66 lumens and provides up to 21 hours of runtime and offers multiple modes (high, low, flashing). Night vision red LED. High- 66 lumens, 7h 15m runtime and beam distance of 22m; Low- 36 lumens, 21h runtime and beam distance of 16m. IPX4- water resistant. Uses three AAA batteries (included). Gray cloth adjustable headband. Hang packaged.