The model number is: AK-194644180591
Yes, it needs a base. Most Eufy products use the centralized base.
. . .and looking on Amazon, apparently they are now selling a combo deal of the battery-powered doorbell and homebase, which is a good bargain. If all you're wanting is just a video doorbell, it's probably your best bet: https://www.amazon.com/dp/B099RX62SC
. . .and if you want to add door sensors, motion sensors, cameras etc. later, that's pretty easy and seamless to add once you've got the homebase set up.