GoPro Hero4 Sound Quality Test - Waterproof Case VS. Skeleton Case - GoPro Hero 4 Black Edition - YouTube
Revo Skeleton Housing for HERO3/HERO3+/HERO4 AC-SHH3PT B&H Photo
SOONSUN Side Open Skeleton Housing Case with Hollow Backdoor and Lens Cap for GoPro Hero4 Hero3+ Hero 4 3 Silver Black Camera: Amazon.co.uk: Electronics & Photo
Side Opening Hole Protective Shell Case Skeleton Housing Box +Touch back door For GoPro Hero 3+ Hero 4 Accessory - AliExpress