Here's a simple way to reuse old vape batteries. A single vape Li-ion battery is a great replacement for 3 AAA cells. This print allows you to replace a triple AAA battery power pack with a rechargable battery from a discarded vape.

This also includes a file for a charging cradle. You can rescue the charging circuitry from another discarded vape.

More detailed instructions on Instructables.com.

Doesn't Matter

No

Both files are simple prints. Use any rigid (non-conductive) filament at whatever setting work best for you.