products recommended on r/wonderswan
ljhnba USB 5V to 1.5V AA Battery Eliminators USB Power Supply Cable Replace 1x 1.5V AA Battery for Electric Toy Clock LED Light
EBL 8-Pack Rechargeable AA Lithium Batteries, 1.5V 3000mWh Rechargeable AA Batteries, Long-Lasting Double A Batteries (Compatible Only with 1.5V Devices)