More power to you?

This is some mad genius engineering here, or at least a very clever trick that you might expect from the kind of person who likes Popular Mechanics. Basically, it takes some batteries in everyone’s favorite size (AA) and lets you repurpose them into batteries in everyone’s most “crap we’re out of those” sizes (C or D).

This is nice. Because it’s way easier to maintain a healthy stash of AAs, which go in all sorts of things, than it is to spend a bunch of money on big and clunky Cs or Ds that you only need a few times a year at most.

By the way, this works with rechargeable batteries in addition to disposable ones, so you can finally turn whatever power-hungry device you have into something that’s at least a little bit sustainable. Are C and D rechargeables even a thing? We’re not sure, but it sounds expensive and annoying.

So not bad for eight bucks! Oh and you’re also going to get a fun Popular Mechanics bonus that will help you keep your various screens clean and shiny. This doesn’t really have anything to do with batteries, but it’s always fun to get a rando bonus item.

Act now to rescue yourself from your next battery shortfall.

We’re positive you’ll be glad you did. Are there any downsides? Negative.