I bought this illuminated multi-power LED head magnifier for $10 in 2013, and I have used it at least a 100 times. That’s 10 cents per use. To use it, you put the band around your head and tighten it with the side knobs so it is snug. It’s comfortable and great for soldering, eyeglass repair, art, lice inspection, and so many other things that require magnification. The LED is powered by two AAA cells (thankfully not coin-batteries) and I’ve only had to change them once (after leaving it on by mistake). I consider this an essential household tool.