THEMAGIC5 Anti-Fog Spray is every swimmer's best friend, and certainly your goggles'. The bottle contains 10ml of Anti-Fog Spray. We have tested this anti-fog spray extensively with THEMAGIC5 goggles, and it works flawlessly. Generally speaking, goggles fog up because of the difference in temperature between the water, the goggles, and your skin. Warm and wet air, usually created from your body heat as you swim, condenses inside the lenses. All THEMAGIC5 goggles feature anti-fog coating when you get them. But this can get worn down with use. If your goggles are fogging up every time you use them, it might be time to consider investing in a new pair or getting this anti-fog spray to prolong their lifetime.