ND Filters are an essential for some types of photography such as moving water effects - and which I suspect I'm overdoing a bit.... And of course there are millions to buy and a huge range of costs. I've tried loads from the super cheap Chinesium resin to some decent quality ones and now this.First off it's optical glass. And that makes a difference because the resin type whilst not bad if you treat then with utter care tend to scratch easily and of course the optical quality no matter what the blurb says is not nearly as good as decent glass.Secondly it's really well made. I mean up there with the stupid priced stuff well made which I've tried and used in a well known camera warehouse. This is a genuine 100% top class bit of kit in terms of the standard of manufacture and the general feel of it. Smooth in action with a perfect optical clarity across the range of density.In use it is super easy. Fit - which is smooth given the well made thread and then rotate the outer ring to the desired level of darkness. It saves a load of faffing with different filters or stacking them.Honestly, if you want a good range of ND filter (not graduated of course) then this is a great choice. I used it on my Zeis Batis lens and it worked a treat.