I bought a couple of the Ultrafire WF-501B LED lights off of Ebay. They are advertised as being 1000 lumen output, and are so bright you cannot look directly at them, day or night. They came with a battery charger and an 18650 Li-ion, rechargeable battery, which I haven't exhausted yet in using the light. I do keep it fully charged, just in case, and have spares if I ever do run it all the way down. I am very pleased with them, and, although I haven't checked what's new in a while, I imagine they have been superseded by newer models. They are small and light enough to carry in my pants pocket, so they are very useful in most all situations. I would suggest at least a 1000 lumens, or more if you can use the larger size. Variable focus would also be nice. You can find various Ultrafire models up to 2000 lumens and above on Ebay for about $10.00. That's with battery, charger, and light. They are well made and, at that price point, you can buy several and throw them away when the battery dies, if you want to.