The Best Underwater Color Correction Filter System for GoPro Hero4, Hero3+, and Hero3 Cameras - YouTube
Kenko Global - Using filters for sea and underwater shooting
Nitescuba Camera Lens 67mm 52mm Circular Polarizer Camera Thread Red Filter Color Light Remedy Underwater Diving Housing Mount - Camera Filters - AliExpress
Guide for the Best Filter for your GoPro - Underwater Photography - Backscatter
Color Filters vs. Post-Processing - Underwater Photography Guide
Amazon.com : CamKix Diving Lens Filter Kit Compatible with GoPro Hero 4, Hero+, Hero and 3+ - fits Standard Waterproof Housing - Enhances Colors for Underwater Video and Photography - Includes 5 Filters : Electronics
Kenko Global - Using filters for sea and underwater shooting
Backscatter Neutral Density Underwater Filter System :: Wetpixel.com