The Luu Extreme 4 isn’t the tidiest or brightest design, but you do get a lot for your money. The single 900-Lumen LED head comes with a selection of diffuser lenses to alter the beam spread.
Unfortunately the broadest spread cap causes a massive output drop to just over 50 lux and there’s a big black hole in the middle of the beam on the most focused setting.
There’s enough light for proper off-roading with the medium filter though and it’s good for the money. Run time is very generous too, and there’s a two-cell version available for £150.
The separate head unit, with metal clip holder, sliding shoe and quick-release mount make it too heavy for helmet use and prone to crash damage. Ours is still soldiering on with some tape and bolt reinforcement though.
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For more information on how we tested this year's crop of lights, see our latest buyer's guide to mountain bike lights and Tested: 30 high-power mountain bike lights.