Product Description: The Fantasea Line Silica Gel Packs absorb moisture and prevent condensation, rust, mildew and corrosion inside your housing. This will stop the port in front of the lens from fogging up. Hot humid air, combined with the heat that digital cameras produce will condensate on the lens as it is in colder water, even if the water is 80+ degrees, it's colder than the inside of the housing. To combat this, use Desiccant Silica Gel Packs that will absorb the moisture inside the housing.
