Snake River Prototyping BlurFix Air with Circular Polarizer Filter for GoPro HERO3/3+/4 Cameras SRP BlurFix Air CP4 Filter For GoPro Hero 3/3+ Fits over the lens of the naked GoPro Hero 3/3+ Perfect For Gimbals and Helicopter Mounts Weighs a mere 7.6 grams Made in the U.S.A. Fast Shipping.