I think it's great quality. I have super clear photos and videos. I believe it's real glass and not the plastic from cheaper brands. Pretty good plastic case. So why only 4 stars. they are a bit difficult to install. It may be a drone design, but I'm used to the M Mini where the filters just snap into place. It requires a little more attention and effort. That being said I still consider them a quality ND filter set and with a little care they will serve you well.