GoPro Hero3 Anti-Fog Inserts prevent condensation that can build up between the GoPro camera and the camera housing. These inserts therefore prevent deterioration in picture quality caused by fogging, which can occur when snow-boarding, skiing and cycling in cold or humid conditions. These inserts absorb moisture. Simply slide 2 inserts into the camera housing on either side of the camera. A pair of inserts should be good for 4 outdoor photography sessions. You can dehumidify and revitalize these inserts, simply by popping them in the oven for 5 minutes. This pack contains 6 pairs of inserts.