How does this hardware mine bitcoin?

I came across a pic of this hardware and initially thought it was a wallet. But after checking out the tweet, a bunch of people mentioned it’s actually mining gear. So, how's it actually work?

usb miners still exist: https://www.bitshopper.de/shop/sha-256-miner/usb-miner-bitcoin/newpac/ You just plug them into an usb port (or powered usb hub), and run mining software on your system, and that's about it... When you start (for example) cgminer, it detects the usb stick and it gets it's work from a pool you configured when starting cgminer, or from your own node. But before you run off and buy such a device, they are not really performant. Most of then never ROI

The image looks like an ASICminer Block Erupter, not the newpac. There are four USB miners that I know that mines Bitcoin the Block erupter, Newpac, Compac F, and Antminer U1 USB miner. But I think only Newpac and Compac F are still available on the market. If you want to talk more about these USB miners then check this thread GekkoScience NewPac / Terminus R606 (BM1387) Official Support Thread. It should be the right place if you want to learn more about this. And take note like the above said it won't make any profit unless it's for study purposes or if you decided to mine solo for lottery.

Ya left out 2 of Sidehacks other sticks: His original Compac and the TwoPac that used the S3 chips. The Compac had 1 chip and the TwoPac had <drum roll please> 2 chips. Und ja, that looks to be a Block Erupter from ASIC miner. I believe it used a chip from Bitfury. Back in the day they were pretty good but these days even compared to an old Compac it is horribly inefficient. Current best stick made is Sidehack's Compac-F that does over 300GHs while pulling less than 15watts.

It worked pretty good.  333Mhash at 2.5 watts vs. my GPU mining rig, of the time, which did 500Mhash at 385 watts. I still have 74 of them.  I would have been better off keeping the Bitcoin I spent on them though