5 Pack K9 Optical Crystal Photography Prism Set,50mm Lens Ball/50 mm Cube/50mm Triangular Prism/50mm Prism Pyramid/ 50mm Crystal Ball for Teaching, Playing, Photography (with 2Pcs Wipe Cloth)

Akamino 5 Pack K9 Optical Crystal Photography Prism Set,50mm Lens Ball/50 mm Cube/50mm Triangular Prism/50mm Prism Pyramid/ 50mm Crystal Ball for Teaching, Playing, Photography (with 2Pcs Wipe Cloth)

Eudax Physics Optical Experiment Set Multifunction Reflector Refraction Triangular Prism Convex Lens Concave Mirror Dial Linear Light Source Teaching Demonstration Equipment-Kids

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