52mm Variable ND Filter ND2-2000 The filter is constructed from optical glass that features 9 layers of anti-reflection coatings on each side(total 18 layers), making the filter anti-scratch, anti-static, oil and water-resistant Compatible with any lens with 52mm diameter filter thread - This variable ND filter is double threaded, has 52mm inner thread(male) and 55mm outer thread(female), this design allows you to put on any 55mm thread accessories such as lens cap, screw-in type lens hood to the front of the filter