52mm Neutral Density Variable Fader ND Filter ND2/1000 FOR NIKON D5000 D5100 | eBay
Amazon.com : High Definition 52mm 10-Stop NDX Neutral Density Variable Filter for Olympus M ED 9-18mm f/4.0-5.6 Micro Four Thirds Lens & Olympus M.ZUIKO Digital ED 12-50mm F3.5-6.3 EZ Lens : Electronics
52mm ND2-400 (9 Stops) Variable ND Filter Neutral Density Adjustable Filter for Canon Nikon DSLR Cameras - KENTFAITH