"The Matrix from ASP Inc. is a lightweight yet street tough tactical flashlight is built for all-purpose, all-weather high performance. The polymer exterior, mated to an aluminum internal frame and wrapped with our exclusive foamed vinyl grip, is preferred by some users for its tactile comfort in cold weather. The Matrix incorporates Dual Fuel Technology, so you'll never be without a power source―it runs with either the included rechargeable 18650 battery, or 2 optional CR123A primary (single use) cells."