LEGO Yellow Electric 9V Battery Box 4 x 8 x 2.3 with Bottom Lid | Brick Owl - LEGO Marketplace
Bricker - Part LEGO - 4760c01pb03 Electric 9V Battery Box Small Complete Assembly with LL-6482 Pattern
BrickLink - Part 87513c01 : LEGO Electric 9V Battery Box Power Functions (Non-Rechargeable) with Dark Bluish Gray Bottom [Electric, Battery Box] - BrickLink Reference Catalog
Build your LiPo rechargeable battery for Control+ and Powered Up hubs. - LEGO Technic, Mindstorms, Model Team and Scale Modeling - Eurobricks Forums