It looks cheaply made, I hope it holds up.
I think the grinding part is ceramic.
One negative is that it doesn't hold a large quantity, and to adjust for a coarser grind, you have to loosen the screw on top.
For the price (€3.5), overall and if it holds up, it's good.

UPDATE: After half a year of continuous use, they still hold up. I have 2, for salt and pepper. So I give them a 4/5 and in conclusion, I say that for the €3.5 I bought them for, they are worth the money.