This is a premium magnifying glass set for newspapers, magazines, books, maps, science classes, jewelry, inspections, crafts, and. It' the perfect gift for a presbyopic or visually impaired grandparent, a set of 20 can be replaced at any time to suit your usage needs Features - Color:Transparent - Material: Acrylic - Size: 4.20X4.20X0.75cm/1.65X1.65X0.29in -Note:One side is slightly convex, other side is very convex. - Made of material: The convex lens is made of polished glass, and the edges are carefully ground and polished without burrs, so very safe - Bi- convex lens: Highly polished bi- convex lens. It can be used on both sides, which is very convenient - Main use: Lenticular lens, can be used to demonstrate optical principles and effects to students, used in scientific experiments and classroom demonstrations, can popularize physical knowledge and stimulate students' interest - Easy to carry: light weight, easy to carry and use, a set contains 20 pieces, which can meet your needs in quantity - Wide range of uses: not can be used for laboratory physics display, but also can be used to observe jewelry, coins,, handicrafts, etc., widely used, easy to replace Package list: 60 x magnifying glass