USB CR123A Lithium Ion Battery, 3.7 V 2550mWh Rechargeable CR123A Battery, 1.5H Fast Charge, 600 Cycles with Type C Connection Cable, Constant Output, Pack of 4 Batteries & USB charger

I initially thought I'd been duped: Amazon had somehow paired four CR123A rechargeable batteries with an utterly unrelated four-port USB-C charger. I was ready to return the items; then I checked what I'd bought and it was a single item: four batteries and a USB-C charger to go with. But where was the cradle that the batteries went into?Then my sharper-eyed other half spotted that the top section of the battery is not battery at all but some electronics, seamlessly integrated into the CR123A body shape, with a USB-C port in it, plus bonus charging lights around the positive nipple.A bit crazy, but it works.