VOLADOR Diving Flashlight, 3100 Lumen Diving Torch Rechargeable, Scuba Dive Light 100 Meters Submersible Lights with 2x 18650 Battery and Charger

I found one of these near a shot in the sea. It’s proving to be a great little backup torch. Been to ~50m in a pocket repeatedly and no signs of water ingress. I’ve cleaned and greased o rings a few times but it seems genuinely pretty good as a secondary or backup light.

A couple years (2-3) into very intermittent use (being stored in a dry area, with batteries removed), this torch sometimes works. The issue I've come across is that I cannot rotate the area where you turn the torch on and dim / brighten the power. This makes the torch useless. This has happened to me during a dive (daytime, so turn it off and on when needed); when I try to turn it back on, I cannot. It also happens on the surface. I don't believe there is enough salt or corrosion to prevent the dial from turning, but I'm not sure what else it could be. I have now purchased a Mares torch, which is quite good, but may have it own faults too.