I haven't been able to try it yet due to quarantine. Its use will mainly be on enduro mtb trails such as Ymittos and Parnitha.

EDIT: I've been using it for about 6 months now, full mountain biking during the summer, etc. At first glance, it seems to have a sturdy construction, definitely not plastic as I have broken several of those in the past. It is a small process to screw it on because you have to make sure it catches well on the two rails of the saddle. In short, the setup takes about 5 minutes, especially the first time when you're not sure. I use it with the Hero 8 Black and it works great... whether in the city or in the mountains, the footage is unique! It's worth the investment to have a follow-cam behind you. To be precise, it is the most stable footage I have ever taken on a bike, especially when combined with GoPro's Hypersmooth 2.0! It's more sturdy than a mount, many times I forget it's on the bike because I'm afraid of losing it.

If anything changes, I will definitely come back.