Streamlight Stylus Pro Pen Light Flashlight - Compact LED flashlights are constructed of durable machined aluminum. The Stylus Pro lights have a patented, proprietary Micro Optical Systems (MOS). The MOS has "Battery-Booster" electronics to provide a super-bright beam. They feature a push button tail cap "on-off" switch, and an LED in white or green that will last for years. The convenient size means it's easy to take these lights along with you, and the light weight makes carrying them a pleasure.