Premium Quality 10.75" x 8.5" Fresnel, Full Sheet Magnifier With 2X Power, Diopter W/ 4X Power This fresnel magnifier is a flat, full sheet size measuring 10-3/4 x 8-1/2 inches The magnifier has 2x power overall, with a diopter of 4x power All four straight edges are designed with ruler markings in SAE & metric (max - 9 inch & 24 cm) This entire fresnel magnfier is entirely distortion free, so reading is easier This magnifier is excellent for full page enlargement, map reading and more