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.