Amazon.com : SOONSUN 3 Pack Dive Filter for GoPro Hero 5 6 7 Black Super Suit Dive Housing - Red,Light Red and Magenta Filter - Enhances Colors for Various Underwater Video and Photography Conditions : Electronics
ND Filter GoPro Session Mount (Smooth Operator) – Catalyst Machineworks
GoPro HERO 9/10/11 - 3 Filter ND Kit - GOPROHERO9NDKIT – The Tiffen Company