I got 2 for the jet x 125. You need 2 right-handed ones. The length of the screw is longer than what fits the jet x 125. You can wrap it with aluminum foil to tighten it well if you don't have a nut!

I bought 2 to see better on my Sym Jet X 125, besides the fact that the fastening screw is bigger (you can make it fit with a washer as a friend suggested), the thread to fit the mirror on top doesn't match the mirrors I wear, so I just threw them in a drawer.
Edit 26/10/23
I finally installed them, it was the mirror thread's fault, it was probably damaged when they were put on the scooter and it had a little play at first, now they provide good visibility, they require a tight fit and don't move, overall satisfied but I think they are overpriced for what they are, hence the 4 stars.

The visibility is greatly improved. The only negative thing is that the screw that comes with it is too long, resulting in it being screwed but not tightened. Maybe my bike has a "shallow" thread - I don't know. It needed a modification to be installed (an additional washer was added, see photo), but everything is fine (the height also increased, so it's better).

They provide better width to the mirrors, for large backs :D and if you wear many clothes they are necessary. A little high price, they are aluminum.