A new store opened up a few weeks ago in my neighborhood. It’s called Daiso and is much like a dollar store except (unless otherwise marked) everything is $1.50. It helps if you can read Japanese because many of the items are labeled in Japanese.
I bought a ‘Hand Pressing Flashlight’ with 2 white LEDS, and I was surprised at how well it worked. And I can’t complain about the price. I squeezed the handle for a few tens of seconds and it charged up enough to run the LEDs for a few tens of seconds.
I can see through the translucent blue shell and I see a motor (actually a generator) and a curved plastic rack of gear teeth. A squeeze spins the motor and it makes a lot of noise when squeezed. My guess is the energy is stored in a battery because the LEDs stay on for so long. If it was a supercap, they would stay bright for only a few seconds.
I bought a “shake” flashlight years ago and it was a big mistake. The shaking gave off light as long as it was shaking, but was very dim when it was still. It performed so poorly that I thought that all hand powered lights would be worthless.
This one is much, much better and a tenth of the price. I have a concern that the plastic gears may fail after some use, but at that price a spare or two for backup is a good idea. If this light uses batteries, it would be best to charge them periodically to keep the batteries from going bad. I think I’m going to buy a few more and take one apart to see what’s inside.