Supposedly 5000 lumens but probably around 3K. It's a bright mutha. I have 3 of them. Ebay
you can find it below 15 bucks but it will come without any chargers or probably batteries. And it takes an odd size battery that is rechargeable. Amazon
has it for around 30 bucks with car and wall charger and a battery set.
Fair construction, comfortable, and I love the side lights for good flood light coverage in mines and caves. Blows most Petzels away. It is not a small headlamp, and one of mine tends to heat up after about 30 min but overall incredible light, you will not miss anything.