Amazon.com : Dome Port for GoPro,Waterproof Housing Case Compatible with GoPro Hero 5 6 7 Black Underwater Protective Diving Dome GoPro Lens Accessories with Trigge Pistol an-ti Fog Insert (for GoPro Hero
GoPro Underwater Housing and Mount Tips - Underwater Photography Guide
How To Use Your GoPro As a Snorkeling + Diving Camera
I might not even use it. (GoPro 11 underwater review) - YouTube