52mm Variable ND Filter Kit for iPhone 13/13Pro Max – Photo & Video Gears
Tiffen 52mm Variable Neutral Density Filter - Newegg.com
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
52mm Bullet Optics Variable HD Multi-Coated Neutral Density (ND) Filter for Canon EF 28mm f/2.8 Lens - Walmart.com
Tiffen 52mm Variable Neutral Density Filter 52VND B&H Photo Video
ProMaster 52mm Digital HGX Variable ND Filter #9308 - Gene's Camera Store
ProMaster 52mm Variable ND #9538 - The Camera Company