Sunglasses can block uncomfortable strong light and protect eyes from ultraviolet rays. All this is due to metal powder filtration devices, which can "select" light when it enters. Colored glasses can selectively absorb part of the wavelength band of sunlight because they use very fine metal powders (iron, copper, nickel, etc.). In fact, when light hits the lens, the light is reduced based on the so-called "destructive interference" process.

Q: Can you do customized designs and package? A: Yes, we offer oem services: 1. you can custom your styles 2. you can custom your mirror lens 3. you can custom your packing box 4. you can custom your logo styles (engraved logo, embosses logo. metal sticker logo, printing logo, laser logo, fixed metal logo) Q: How about your delivery time? A: the specific delivery time depends your quantity Q: How can i get the price? A: pls sent the inquiry to us, we can quote the price within 12 hours Q Can I get a test or sample order first before bulk purchase? Yes, that's no problem, a test or sample order is also welcomed initially. Q. Can you refund the sample cost when I place order? Yes, sample cost will be deducted from deposit of the mass order. Q: What's the warranty? We are very confident to our products. Before sending out, we will check out each single one and pack them well. But to avoid any subsequent trouble, please check on your glasses upon receiving, and keep us informed if there is any damaged ones. For glasses with quality issue, we have policy to re-deliver to you for free.

In other words, when some wavelengths of light (here refers to ultraviolet A, ultraviolet B, and sometimes infrared) pass through the lens, they will cancel each other on the inside of the lens, that is, in the direction towards the eyes. The overlapping of light waves is not accidental: the combination of the peaks of a wave and the troughs of its adjacent waves leads to mutual cancellation. The phenomenon of destructive interference depends on the refractive index of the lens (that is, the degree of deviation when light passes through different substances from the air) and on the thickness of the lens. Generally speaking, the thickness of the lens changes little, while the refractive index of the lens varies according to the difference of chemical composition. And sunglasses should not be in direct contact with the sun.