Joe Rossignol, MacRumors:

OtterBox’s stackable wireless charging system OtterSpot includes a base that can charge up to three disc-shaped 5,000 mAh batteries and an iPhone, AirPods case, or other device on the top simultaneously. The idea is that you can quickly pick up one of the batteries from the stack and charge any Qi-enabled device on the go.

This is clever. Wasteful, in the same way as any inductive charging system, but definitely clever.

Stack up the batteries, grab one when you are on the go, and you’ve got a battery-based Qi charging system with you on the road, and it’ll be freshly topped off.