Review on 🔦 COSOOS Waterproof LED Headlamp Flashlight with Carrying Case - Lightweight Head Lamp for Camping, Running, Reading - No AA Battery Required by Cameron Aleman

Gives solid light from ONE AA battery! This is not usually possible as LEDs require at least 2.4 volts and an AA battery is half the size. This cheap and lightweight headlamp uses a "Joule Thief" circuit that pumps a lower voltage to a higher voltage. This is great for two reasons. First, a cell weighs much less. Less than an ounce on my head. Second, you now have the use of that box of half-depleted AA batteries. (A lot of electronic devices stop working when the battery is dead, but not dead. Save them and use them with this headlamp to suck up the last bit of power. So basically three batteries. Great light weight well thought out product!