Designed an 18650 to 2x D Cell adapter with charging for my Maglite. : r/flashlight
Aaa To Aa Battery Adapter 2aa To D Battery Converter Holder Aa To C Battery Adapter For Battery Converter Adapter Case - Battery Accessories & Charger Accessories - AliExpress
2AA to D Cell Battery Adaptor Holder Case Converter Switcher AA to D Battery Adapter AA to C Battery Box AAA to AA Size Box | Lazada
3x 18650 Li-Ion to 4D-Cell Maglite ADAPTER- Flashlight conversion w/ LED option | eBay