We just got these in, so to be honest we haven't tested them yet, but they look very promising. They're 1000 lumen helmet or bar mount lights with lithium ion batteries and a 2.5 hr run time in their brightest setting. They come highly recommended and they're from Serfas, a name we've really come to trust. They're $299 each, which ain't cheap, but considering the illumination they provide (you should be able to race at close to full pace through trails at night) they look like a pretty great value.
If you're looking more for the types of lights that allow you to be seen, as opposed to seeing, we have stuff in stock for a fraction of the cost. If you want to see well in dark places this is the item for you.
We'll put this product through the gears soon and update you with the performance - we're looking forward to tests!