Polaroid Optics 52mm Neutral Density Camera Filter ND 0.9 - PLFILND952 | eBay
Tiffen 52mm Variable Neutral Density Filter 52VND B&H Photo Video
Amazon.com : K&F Concept 52mm Variable ND Filter ND2-ND32 Camera Lens Filter (1-5 Stops) No X Cross HD Neutral Density Filter with 28 Multi-Layer Coatings Waterproof (Nano-X Series) : Electronics