Streamlight manufactures lights for law enforcement so you can expect the level of quality that comes with such a demanding position. The SL-20L is truly a light for professionals - a large and powerful light for getting work done. Ideal for use by law enforcement, fire and rescue, security, automotive work, and a variety of jobs around the house. The push button barrel switch lets you alternate between High, Medium, Low, and Strobe output modes. On High the SL-20L puts out 350 lumens for up to 2 hours of continuous use while on low only puts out 10 lumens, but for an incredible 50 hours. The deep dish parabolic reflector throws a tight beam with strong peripheral illumination. The SL-20L can withstand the elements of demanding work environments and weather conditions. The case is made of machined aircraft grade aluminum (anodized to prevent corrosion) and the polycarbonate lens is virtually unbreakable (and O-ring sealed). The SL-20L has an IPX4 water resistance rating and an impact resistance of 1 meter. This is a light built to last. The rechargeable 5-cell nickel-metal hydride battery gives the SL-20L next to non-existent operating costs. This model includes a 120-Volt AC charger, 12-Volt Dc charger, two charger sleeves, and works with existing SL chargers. If you are tired of constantly replacing batteries and you want a light that will last you for years the Streamlight SL-20L is the light for you.