The original Fuel, introduced in 2007, quickly became a go-to headlamp, with a sturdy, lightweight, and functional design at a friendly price. The new PRINCETON TEC FUEL ($26.99, princetontec.com), however, keeps the same price but adds a fourth 5mm Ultrabright LED, upping the brightness by 10 lumens. Still in play are the big pushbutton power switch; pivoting, water-resistant body; and four modes (low, medium, high, and flashing). The new Fuel weighs 2.75oz and runs on three AAA batteries (included).