Trail Tech's MR11 lights pump out an eye-searing 500 lumens from their 13 Watt high intensity discharge lamps - that's equivalent to a 76 Watts of halogen power. With the twin set you get a spot and a flood, so both immediate terrain and distant obstacles are lit up with the white light.
Intended for motocross and quad bhike use, Traitech's range is worth checking out for mountain biking. The MR11 helmet lights use a simple sliding mount or supplied handlebar mounts for any size bars.
The battery units are bigger than most bike-specific units, but with the helmet mounting they can sit in your riding pack. If you're mounting them to your bike, you’ll need to stow them in a bag, or get jiggy with the duck tape, which isn’t ideal.
The units are neat and well sealed, although the power switches aren’t on the units themselves – they’re on the cables, annoyingly at the battery end.
They have a simple on/off switch and an LED to signal their status. The NiMH battery takes three-four hours charge, and will power one light for four hours, or two for two hours.