Compact, waterproof construction withstands tough work environment. .5 watt high-flux LED has a 30,000 hour lifetime so it never needs replaced - saves user money on bulb replacement costs. Proprietary Micro Optical System (MOS) for optimized output (super bright beam) and run time. Shock proof - drop test verified above the industry standard of 6 feet. Unbreakable pocket clip and ring for easy storage/attachment MicroStream LED pen light features a super bright, high flux, 1/2 watt LED. Corrosion and waterproof construction with an unbreakable polycarbonate lens and pocket clip. Rubber push button tail cap "on-off" switching. Provides up to 20 lumens for up to 1.5 hours. O ring sealed. 3.5" long and includes (1) AAA alkaline battery.