LIFE TIME WARRANTY -100% risk free to try, unsatisfied glasses can be refunded within 90 days of receiving. Customers will enjoy lifetime warranty(not man-made damage). In case of any problem happening, just contact us without any hesitation until you are satisfied. FRAME TECHNICAL CHARACTERISTICS - 1.Light weight Metal frame for less pressure on your nose. 2.Replaceable lens to meet your reading glasses or sunglasses needs. 3.High wear-resistance, hard to break and 90 days return policy is another quality warranty. 4.Skin friendly without causing allergic reactions. LENS TECHNICAL CHARACTERISTICS - 1.Multifunctional coatings,like UV400 protection, anti scratch coatings. 2.Reasonable blocking rate. Firmoo computer glasses lens' blocking rate is designed considering two reasons:Higher rate would cause color distortion, lower rate would not protect your eye effectively. NO MORE TIRED EYES - We are directly exposing to blue ray from phones, TVs and computer screens over 8 hours every day,please don't worry,Firmoo computer Blue Light Blocking Glasses help you with discomfort like eye strain, migraine, blurred vision and hard to sleep. DESIGNED FOR DAILY USE - When you spend much time on social media, Firmoo anti blue ray glasses help to reduce eye strain and headache by blocking blue light for you. Besides protecting your eyes, Firmoo oversized glasses are perfect accessories to show yourself on social media.Special designed rectangular frame looks stylish,which would shine your style out from other people. Arm: 149 millimeters. Bridge: 19 millimeters. Lens height: 45 millimeters. Lens width: 53 millimeters. Anti-Reflective Coating coating. Non Polarized. Plastic lens. TR90 frame. Imported.