The GoPro Hero 3 Anti-Fog Inserts drop into the sides of the camera housing to prevent fogging in cold and humid environments. To Reuse: Inserts will last for approximately 4 uses. To dry out and reuse, heat inserts on a pan in oven at 300 F for 5 minutes. Store in an airtight bag. For use with all cameras. Features: 12 anti fog inserts Can be reused upto 4 times For use with all cameras