The quality is better than that i thought. I really wish i could place some pictures on thomann to show you all! The surface is really smooth and better on the pictures. The roller goes smoothly and keeps stable. For some guitars the screw might me a bit too tall, be sure to measure the thickness of your headstock otherwise the screw will go right through! For the people who need the measurements: the screw is 1,5 cm the string roller is 1,2 cm in total. I would recommend this string roller as an great upgrade! It keeps your strings much more in tone than a average string pusher and its not as big as i thought. I also heard from friends who used this roller, that its great for tremelos too, but thats up to you all to find out!
Pros
Smooth
Good measurements
Rolls fine
Good tonation
Keeps in place
Can be placed anywhere where needed
Cons
Screw might be a bit too tall
In short: stable, smooth, good string roller from a well known brand Göldo. Would recommend this for anyone who wants something special on their guitar or simply better quality.