If you look at the inside of double lens goggles, you will see a small, round white sticker (with the exception of some product numbers).
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Round sticker on the edge of the lens
For those of you wondering what this is and trying to peel it off with your fingernails, please wait a moment!!
This small sticker has an important role. Do not peel it off under any circumstances!!
Have you ever had this experience?
If you take an unopened bag of potato chips or bread purchased at low altitude to a place at high altitude, it will swell up.
The same thing happens with double lenses, which have two lenses in close contact with each other. At high altitudes, the difference in air pressure causes the lenses to expand, distorting your vision.
To prevent the air pressure difference between the inside and outside of the lens, double lenses have a small hole in the inner lens that allows air to pass through and adjust the air pressure. However, simply drilling a hole allows not only air but also moisture to get inside the lens, causing fogging between the lenses.
That's why we affix a seal (APA filter seal) to the air pressure adjustment hole, which acts as a filter that "lets air through but blocks moisture."
This is the true identity of the "small, round white seal." It plays an important role in maintaining the optical performance of the lens.
APA stands for Atomospheric Pressure Adjustment
*The color of the sticker may vary depending on the year and lot of the goggles produced.
For the same reason, a sticker may be affixed to the inside of the inner lens.
