Martini M31 sunglasses Feature Martini's New 8 Layer "Ultra Polarized" GlassLenses with "Hardshell" proprietary scratch resistant coatings, "AR" anti reflective treatment to reduce rear and side glare and an Oleophobic coating which includes a Hydrophobic treatment that seals the lens surface and reduces the adhesion of grease and water. This makes a lens very easy to clean. These lenses are the Best in the World! The M31 features a Handmade Acetate frame fitted with Italian Optical spring hinges. Eye size 56mm. Bridge 17mm. Temple length 115mm. The M31 is 45mm or 1 3/4 inches tall and the overall width is 130mm or 5 1/8 inches. This style is very similar to the Martini M36 but more squared off lenses. The M31 and M36 are great sellers.