Thank you for viewing! (*^-^*) Instant purchase is OK. ★ Photochromic Sunglasses 【Color】 Black They are clear glasses indoors and sunglasses outdoors. These are 2-Way Lens that change the density of the lens color depending on the amount of UV light. Perfect for travel and outdoor scenes! ☆ What are photochromic lenses? Photochromic lenses are lenses that change the density of their color depending on the amount of UV light. They change to colored lenses when exposed to UV light outdoors, and return to clear lenses in places where UV light is not present, such as indoors. They work as both glasses and sunglasses with just one pair. The density of photochromic lenses changes automatically depending on the "amount of UV light" and "temperature." The more UV light, and the lower the temperature, the darker the color becomes. The color tends to be darker on a clear winter day than on a hot summer day. Unisex. They look great on men, and also look cool on women. The lens density outdoors will be light sunglasses when there is little UV light, and darker gray when there is strong UV light! ☆ The lens color will not change inside a car, etc., within UV-cut glass. ☆ It takes some time for the color to fade after it darkens, so please be careful when entering dark places such as tunnels. Polarized lenses Outdoor Camping Glamping Polarized sunglasses Photochromic sunglasses UV cut Sunglasses Women's Men's Driving Sunglasses that change color Frame color...Black Lens features...Polarized sunglasses