Pulley Large Demonstration Single, Designed for Classroom Demonstrations, Light-weight, low-friction, and deformation-resistant plastic ensures accurate results, Open to make it easier for users to run pulley cords through them
Double Convex Lens, Highly polished, optically true lens is excellent for physics classroom demonstrations in optics and light refraction, with ground edges, great for physics classrooms, with highest grade, Size: 100 mm focal length, Lens measures 3in diameter, 0.3 weight