flashlight

Wurkkos TS27 has an LFP battery and is beefy and advertised as a duty light, and it seems nice except then it has this silly RGB ring light that turns it into a fidget toy. I lost interest because of that. YMMV. :)

https://wurkkos.com/products/ts27

Added: I just looked over the kickstarter page for this light. The battery looks to be 10,000mAH nominal, size 32140 which is 4.7x the volume of a 21700. Voltage is 3.0 nominal but looking at the discharge curve at -20C it looks about 2.5V on average, so 25 WH. Not that much better than a 5000mAH 3.6V 21700 (18WH). The sodium is somewhat worse but still viable at -40C and I guess it might be beating lithium by then too, plus it has the ability to accept charging at -40C. I don't see super-cold charging as very important for a flashlight (if you're able to charge your light you can probably keep it at least a little bit warm), though super cold operation can be helpful.

Also, this is a 2500 lumen light which is a far cry from the old Maglights that were perfectly usable. The classic 2AA minimag was around 5 lumens over most of its runtime, the huge 6D was something like 36 lumens, and the nicad powered Magcharger was about 180 lumens. Surely for changing a fuse, a low powered headlamp is preferable to a huge handheld ;).