A brief introduction to the Teenage Engineering Pocket Operator PO-12 Rhythm synthesizer.
https://www.teenageengineering.com/products/po
Addendum: You can turn on a click-track (metronome) by pressing Function + BPM. This cycles through sync modes, which include an audible sync-click on the beat. There are 6 sync modes, 0 being the one you will want to return to when you're ready to play without a click again.
Sorry about the strange noises in the VO, still getting used to my new lav microphone.