Battery Charger
Not a battery recharger: a battery charger. You plug it into the wall, you pop in a standard-sized non-rechargeable alkaline battery into one of the slots provided (from AAA to E), and within half a minute it charges up the battery for you from wall current. It always works. It doesn’t seem to hurt the battery. It doesn’t care what brand the battery is, or how old it is. You can buy a Battery Charger from a sidewalk vendor in most major cities in the Americas for about twenty bucks.
Just don’t show one to a chemist, unless of course you like seeing people have nervous breakdowns. The Battery Charger cannot actually work, because non-rechargeable alkaline batteries rely on a particular kind of chemical reaction that can’t be reversed simply by shooting enough electricity through it. Unless you have a Battery Charger, apparently. The Battery Charger does things to the internal composition of the battery it’s charging that the charger, well, simply shouldn’t be able to do. And neither the chemists nor the physicists who will end up looking at one of these devices will be able to make heads or tails of it. But the Chargers work! Somehow.
Anyone researching Battery Chargers (instead of simply and resolutely ignoring their existence, which is what most of the mundane scientific world is doing) will discover that the devices are coming from an obscure Brazilian manufacturing company. Research of that company will soon determine that they started making the items six months ago, and have been slowly building up a distribution network for Battery Chargers based on word of mouth advertising.
Even a small amount of pressing will get the company owners (a brother and sister) to open up. In fact, if the party works for anything at all resembling ‘the Secret Masters’ the company owners will spill everything, immediately, because they were certain that the Illuminati would come by eventually to make inquiries. Now that the day has finally come, it is the ambition of the siblings to sell their enthusiastic silence at a very reasonable rate. They would also not say no to being actually seduced, but neither is inclined to push the matter. Too much.
Eventually, the party will be told about one “Juan Ferreiro“ who hired the company the year before to do some fairly precise metal and electrical wiring work. The man was a bit of a condescending ass who wanted to pay in industrial diamonds and gold wire, but he was eventually persuaded to get a bank account like everybody else; and while his Portuguese was serviceable, it was fairly clearly not his native language. Then again, neither was French or English — Mr. Ferreiro claimed to be from Canada, which was frankly ridiculous — but as far as either sibling could tell they weren’t making anything illegal, and they certainly weren’t making weapons.
They instead assumed that the man was some sort of space traveler or something who needed to quietly repair his starship, which is why the company happily took his money while quietly making copies of all of the documents and blueprints Mr. Ferreiro provided. The Battery Charger was one of them; the company decided to duplicate it first because it was easy enough to fabricate, and didn’t require any exotic materials. They have other blueprints and schematics, of course.
Well, copies of them; the originals quietly dissolved two days after Mr. Ferreiro closed out his account and picked up his final orders. That was one day after people reported on a weird set of flashes in the sky to the south of the city; the siblings have their own opinion on that, but they’ll be happy to arrange for introductions to some of the more reliable eyewitnesses. Why? Because these two really want to be helpful. In that way that people get when they kind of want to be recruited into the Conspiracy.
And, to be fair: the Conspiracy has encountered far worse potential recruits.