Lens Bi-convex - 50 mm, 100 cm Focal LengthGlass Lens Biconvex, with a 50mm Diameter and 100mm Focal Length. These lenses are sold in a pack of 10 perfect for exciting experiments in your classroom! Bi convex lenses are thicker in the centre of the lens than the edge, and can be used to focus light among other things. Units: pack of 10 Each product is carefully designed by a team of laboratory professionals and experienced engineers with quality and durability in mind. They are manufactured