Mirrored sunglasses

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Mirrored sunglasses are sunglasses with a reflective optical coating (called a mirror coating or flash coating) on the outside of the lenses to make them appear like small mirrors. The lenses typically give the wearer's vision a brown or grey tint. The mirror coating decreases the amount of light passing through the tinted lens by a further 10–60%, making it especially useful for conditions of sand, water, snow, and higher altitudes. Mirrored sunglasses are one-way mirrors.^{[citation needed]}

The color of the mirror coating is independent of the tint of the lenses. It is determined by the thickness and structure of the layer.

Their popularity with police officers in the United States has earned them the nickname "cop shades". The two most popular styles for these are dual lenses set in metal frames (which are often confused with aviators), and wraparound (a single, smooth, semi-circular lens that covers both eyes and much of the same area of the face covered by protective goggles, combined with a minimal plastic frame and single piece of plastic serving as a nose pad). Wraparound sunglasses are also quite popular in the world of extreme sports.