I've ordered six of these lights in the past. Three immediately went back because they didn't work out of the box. They are very cheaply made and are $20 for a reason.

They are also nowhere near 1000 lumens. That's the theoretical max of the LED, not how many actual lumens it pumps out. Realistically, it's about 600-700 at most. That's still awesome for $20, but it's nowhere near 1000 lumens.

This one: http://www.amazon.com/SecurityIng%C2%AE-Waterproof-Bicycle-Lighting-Flashlight/dp/B00C2MHNJK/ref=sr_1_4?s=sporting-goods&ie=UTF8&qid=1414784449&sr=1-4&keywords=securitying is a much better made light. I have two of them and they have a better beam pattern and have lasted a lot longer than the single beam ones. It's nowhere near 2800 lumens though. Again, that's a marketing claim based on a theoretical max.

I use the dual beam on my helmet, and the single beam with a wide beam diffuser on the handlebars. It's a great combination. The use the same battery pack, so if one dies, like it did on my last ride, then you can just swap the battery pack to the helmet.