Like many other manufacturers, Mag Instrument has expanded its line of flashlights to include models featuring LED-type bulbs. Why? LEDs are virtually unbreakable, and they are far more efficient than incandescent bulbs. As the product name suggests, this Maglite runs on 3 D-type batteries, which will take a while to run out thanks not only to the LEDs but also to Mag Instrument's Intelligent Energy Source Management, which balances high brightness against extended battery life. The bright, powerful beam adjusts from spot to flood simply by rotating the head. The case is made from a high-strength aluminum alloy that has been anodized inside and out, which gives you water- and shock-resistance in a lightweight package. High-quality O-rings at both openings keep water away from the batteries.