SOLAR SHIELD Sunglasses Polarized Solar Shield CLIPS over your regular GLASSES. 51 Rec B lenses Polarized lenses block glare. Blocks 100% UVA/UVB. How can I be sure that I am ordering the correct clip ons ? There are two ways to determine which clip ons will best fit your glasses: 1) The first and the most accurate method " Our recommended method ", is to simply take the following measurements directly off of your glasses, A)The shape of your Frame B) Frame Height = mm (Note 1 inch = 25.4 mm) C) Frame Width = mm (Note 1 inch = 25.4 mm) D) Overall Frame width = mm (Note 1 inch = 25.4 mm) Please Note: If your exact dimensions falls between two different size clip ons, we recommend that you pick the larger of the two. Lenses exceed ANSI Z80.3-2001 strictest UV blocking requirements. These have a limited lifetime guarantee from the manufacturer, Dioptics Inc. The packaging is actually a really nice plastic box to store them in. Solarshield Clip X-Span.