Thomann Sound Olives

This is not a percussive instrument. I can't imagine anyone keeping the rhythm with these things.
It's two metal bead-shaped magnets. They produce sound similar to two big metal balls hitting each other, and then processed with a quick pitch shifting delay. So, you get something like a short "BZzzng".
You can make some frequency range of that sound ('more highs' or 'more mids') more pronounced, depending on the way you're holding the beads.
You can hold one bead and drop the second from 1-2cm. You can put ring finger between them, and then trigger the upper part of one of them using index finger, thus 'playing' it with a single hand.
All in all, a very limited range of sounds and very complicated to keep rhythm with. Also, the sound is not useful in most of the music genres. If you do need it, you'll probably sample it and then use beads as a fidget.