20 Pcs Optical Lens - 42mm Diameter Double Convex Lenses, 68mm Focal Lengths Biconvex Lens Magnifying Glass Lens

Optical 3D Lens for Magnifier - 20 Pcs 42mm Diameter Double Convex Lenses 68mm Focal Lengths Biconvex Lens Magnifying Glass Lens Optical Plastic Lens

Amlong Crystal Premium Optical Glass Double Convex and Concave Lens Set, 50mm Diameter, 3 Double Convex (20, 30, 50cm FL) and 3 Double Concave (20, 30, 50cm FL), 6 Piece Set

EISCO 6pc Optical Lens Set, 2" (50mm) Diameter - 3 Double Convex Lens & 3 Double Concave Lens - 200mm, 300mm, 500mm Focal Lengths - Optically True Glass - Ground, Beveled Edges