Previous page Function Oriented meanwhile Stylish Wear Alone or Wear Over Prescription Glasses TAC Polarized Lens Filtering Harmful Rays High-Definition UV400 Balancing the Colors Perceived Dual Slot Design Glasses Stay Stable When You Are Moving Light & No Burden Ultra Light Material No Screw Structure Next page 1 Fit Over Glasses 2 TAC Polarized Lens 3 Stable 4 Ultralight Polarized UV Protection Lens Anti-Glare / HD Vision / True Color How To Measure Step 1 Your prescription glasses (Measure from Front) Measure the widest part of the frame, which is the"Width". Then measure the highest part of the frame from top to bottom, which is the "Height". Step 2 Our Fit Over Sunglasses (Measure from Inner) Width: 143 MM / 5.6 IN Height: 50 MM / 2 IN If both Width and Height of your prescription glasses are shorter than above data of our Sunglasses, then these fit. Fits Over Your Glasses Use our sunglasses fit over glasses for most outdoor activities such as driving, hiking, boating, biking, fishing etc., protect your eyes from the harsh rays of the sun, no more struggling so bad during the winter with the reflection of the snow or to see fish in water on the glistening water/lake/pond's surface, also a great helper for someone who just has eye sensitivity to glare. SIZE CHART Medium (Brown Leopard/Brown) Large (Grey Leopard/Brown) X-Large (Blcak/Grey) Medium M: 143 * 42 MM (5.6 * 1.65 IN) Large L: 143 * 50 MM (5.6 * 2 IN) X-Large XL: 143 * 50 MM (5.6 * 2 IN) Oval Suitable for slim glasses Cat Eye Suitable for most glasses Cat Eye (Wider Lens) Suitable for large glasses Polarized & UV400 Protection Fit Over Glasses Polarized & UV400 Protection Fit Over Glasses Polarized & UV400 Protection Fit Over Glasses