Double Convex Lens, 300mm Focal Length, 3" (75mm) Diameter - Spherical, Optically Worked Glass Lens - Ground Edges, Polished - Great for Physics Classrooms - Eisco Labs sold2024 1000 mg of vitamin C

1000 mg of vitamin C taken daily for 4 weeks bolstered vitamin E and glutathione content in erythrocyte cell membranes

which operates using three C batteries (not included)

Used by plumbers to repair American Standard products

And it also very sharp

Double Convex Lens, 300mm Focal Length, 3" (75mm) Diameter - Spherical, Optically Worked Glass Lens - Ground Edges, Polished - Great for Physics Classrooms - Eisco Labs sold2024 1000 mg of vitamin CDouble Convex Lens, 300mm Focal Length, 3" (75mm) Diameter Spherical, Optically Worked Glass Lens Ground Edges, Polished Great for Physics Classrooms Eisco Labs Product Features DOUBLE CONVEX Highly polished, double convex lens SPHERICAL Lens measures 3" (75mm) in diameter 300MM FOCAL LENGTH Converging lens with a 300mm focal length OPTICALLY WORKED GLASS Made of high quality, optically worked glass. Highly polished with ground edges GREAT FOR PHYSICS