3R12 3LR12 battery adapter for old flashlights

It uses AA battery holder from aliexpress, like one shown in the last picture.

I suggest printing it on it's back.

You will need 2 strips of metal, preferably terminals from old battery.

Wires are meant to be screwed in to terminals, but i guess you can also solder and glue them in place.

If you want to install LED light bulb in your flashlight, pay close attention which terminal should be the long one. Unlike orginal battery i had to reverse them and make positive terminal longer.

Link to battery holder i bought from aliexpress:
https://www.aliexpress.com/item/4001008150456.html