Keep it in your pocket or stashed in your pack, the Black Diamond Ion is so light and compact there's no reason to ever be left in the dark again. Great as an emergency backup or as your primary light for featherweight expeditions, the Ion is the size of a book of matches. One bright 0.5-watt LED bulb lights the way; high and low settings let you determine how much light you need. Pivotable head allows you to aim the beam where you need it most; tough construction withstands use in rain, snow and sleet. On/off switch requires you depress the button for one second to turn on, reducing inadvertent, battery-draining operation while stowed in your pack. Slim half-inch elastic headband adjusts with a slider to fit over a climbing helmet or a hat. Battery included.