Amazon.com : K&F Concept 37mm 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
ProMaster - 77mm Variable ND Filter
PRO 82MM Variable ND Extreme - HGX Prime (5.3-12 stops) - Looking Glass Photo & Camera
JJC 43mm ND Filter Variable Neutral Density Filter ND2-ND2000 for Camera Lens | eBay