Yes. A magic one.
He gives the numbers that help you know….Input and Output.
Input is 3 to 4.2 volts, which is what’s normal for a single lithium-ion cell.
Output is boosted alllll the way up to 12 volts! Woohoo! And at that voltage has a current of 2.5 amps.
I’ve always thought boosting was a little magical. It’s easy to grasp the idea of a buck driver, where “extra” voltage is just diverted and wasted as heat…like flattening a heaping scoop of coffee grounds (which is sinful). But making more out of less is pretty special…especially when bumping it up to 12 volts instead of the much more common 6 volt boost needs. This is chosen by the particular emitter, of course.
If you look at the photo of the top side of the driver, that big grey square is an inductor, and that along with some other components is making it all happen. Some inductors look like little black cylinders, maybe with a black shrink wrap around them or maybe without, allowing bare copper wire winding to be visible…and some look like little glittery charcoal briquettes…lots of different types of inductors and they can be used for both buck and boost purposes (either/or, or both at the same time, depending on the circuit design).
Now on the flip side, take a look at this one from him…it’s a buck driver but it looks very much alike: 6.44€ |17mm fahrer, eingang: 3 8,4 V, ausgang: 3 4V 1200mA (single mode)|Taschenlampen| - AliExpress
That one tells you that the input is from 3 volts up to 8.4 volts, which would be the voltage of one single cell or two cells in series. Since normal 3v and 6v emitters will likely go poof if you press 8 volts into them from two batteries, this driver bucks off that extra higher voltage to regulate it into something that protects the emitter at a normal 3-4 volt range (the voltage an emitter uses is variable while in use and depending on current and binning, within a small range). Big fat square inductor but it’s being used for a different purpose here (it’s no doubt not the exact same spec inductor as on the other driver, but just as an example of the dual-purpose).
Here’s a pic of a different old-school kind of inductor, still popular in many designs and devices: 11.3€ 5% OFF|Super Output SSC P7 Led treiber Bord (Low/High/Mitte, 5,5 V ~ 15V)|board|board boardboard led - AliExpress
And an even older-schooler inductor with a fat iron donut wrapped with wire: https://www.aliexpress.com/item/32760098085.html
All this inducting business is the magic of magnetism, by the way…same as in A/C motors and many other electrical things. The energy in naturally produced magnetic forces is built up or torn down to different levels and used for world domination.