Snake River Prototyping BlurFix3 SO Cyan Dome Filter for GoPro HERO3/3+/4 Cameras Snake River Prototyping BlurFix3 SO Cyan Dome Filter for GoPro HERO3/3+/4 Cameras - Lanyard String - Snake River Prototyping 1 Year Warranty URPRO polycarbonate dome filter designed to match performance of optical glass filter ring constructed from CNC-machined Derlin, a synthetic polymer known for stiffness and stability