This filter is very made of aluminum, slim and very light. Very well constructed.
Because this filter is 52mm , but designed to fit a 50mm size lens, you will not be able to :
1. attach your lens cap (maybe a 52mm lens cap would fit)
2. attach your lens hood
3. attach any other filters to this one. You are able to attach 50mm filters to your lens, and then stack THIS one onto those filters. I did this with my CPL filter, but found it difficult because I had to rotate the CPL , and then rotate the Variable ND filter, so I removed the CPL for now.
Also, I need to investigate whether it is even advisable to use a CPL and ND together because of the low-light.

It is really a nice feature of this filter to incorporate 1 to 11 stops on this one variable filter. It makes it easy to dial to the stop that you want to use, but I found it a little confusing. The stops are labeled with Min on one end, Max on the other , and 8 dots in between.
So I'm not really sure what dot corresponds to what ND stop, there are supposed to be 11 stops, but there are only 10 markings.
Also , there is no lock at the beginning or end of the 10 stop markings.

Anyway , I've been experimenting and getting to learn how to use it.
I see how it it very convenient to have only ONE Variable filter, instead of several. Much less exptensive, much less complicated. But it is going to take me a little bit of time to learn how to use it efficiently.