Fotodiox Pro WonderPana Go H3 Filter Adapter *Not HERO3+ Slimcase* – Fotodiox, Inc. USA
GoScope (60M) Red Filter - Compatible with GOPRO HERO4 / HERO3+ / HERO3 Dive HOUSING (60M Case Only) Laser Cut Optical Red Filter See Pictures to Make Sure This FITS Your Camera CASE
GoPro Hero3 Red Dive Filter-Snap On Accessory GoPro Hero3 White Silver Black | eBay
Polar Pro - Filter - polarizer - for GoPro Housing; HERO3; HERO3+ - Walmart.com
6 Piece Filter Kit for GoPro Hero 3/4 - Red Purple Pink Gray Orange Yellow | eBay
SRP - SWCY Filter for GoPro cameras | GoWorx®
Amazon.com : CamKix Cinematic Filter Pack Compatible with GoPro Hero 4 and 3+ Includes 4 Neutral Density Filters (ND2/ND4/ND8/ND16), a UV Filter and a Cleaning Cloth. : Electronics