Originally Posted by Looigi

I use a Planet Bike Blaze 2W light that uses 2AA batteries. The batteries last quite a few hours in flash mode, but I never determined quantitatively how long. It's probably a bit over 100 lumens and has a intense multi flash (one very bright followed by 3 lesser flashes) that I can see hitting reflective signs up ahead when cloudy or just after the sun starts setting. Weight is 126gm with bar mount. It doesn't come with or have a helmet mount that I'm aware of. I think you can find the lights for around $30.