have come to rely on K&F for a number of filter types for my many lenses. They are well made with quality glass and I have yet to find any real faults or negatives in these great value filters. You would have to pay a TON more for filters that are only slightly better than these! This variable ND3 to ND1000 filter provides highly capable ND correction from 1.5 to 10 f/stops. It is a 67 mm filter that is widely used...especially for the majority of Tamron lenses as well as a plethora of Sigma, Sony and Canons as well, which makes this filter an even better bargain. The variable range is done simply by rotating the front dial of the filter until just the right ND level is found in the viewfinder. The filter features 24 multi-layer coatings to provide the clearest and distortion-free optics, using Japanese glass (Excellent) and precise CNC machining. I can honestly say that this variable ND filter is almost as good as filters that cost as much as five times more. Construction is very good and the filters mount to appropriate lenses without drag, rubbing or other issues. Simple operation and fantastic results! All in all, and especially at the value price, this set earns an easy FIVE STARS with me, and I can honestly and heartily recommend the set for your appropriate lenses.