5cm Focal Length 30mm Double Convex and 7.5cm Focal Length 30mm Double Concave Lens 1 Set, 2 Pack Glass Optically Polished Round Edges Lens for Physics Experiment Classroom, Clear

PATIKIL 5cm Focal Length 30mm Double Convex and 7.5cm Focal Length 30mm Double Concave Lens 1 Set, 2 Pack Glass Optically Polished Round Edges Lens for Physics Experiment Classroom, Clear

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