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.