FLIP11 Two Filter Kit with DIVE & DEEP Filters for GoPro HERO 5, 6, 7, 8, 9, 10, 11
Do You Need a Polarizing or ND Filter for Your GoPro? [PolarPro Filters Review] - VidProHero
Amazon.com : CPL Polarizer Filter for GoPro Hero 11/10 / 9.with The Filter Adapter, You can Also use All 52mm Camera Lens Filters on Gopro 11/10/9 : Electronics
For Go Pro Hero 3 / 3 Plus / 4 Session 37mm / 40.5mm / 52mm / 58mm Gopro CPL Filter Circular Polarizer Polarizing Lens Filter for Gopro Hero 3 3 Plus 4 Session | Wish