6-Piece Optical Lens Set, 3", Double Convex and Double Concave Base_Octagonal supporting three-rope compound arrangements for

supporting three-rope compound arrangements for advanced mechanical-advantage investigations

101-piece teacher-grade molecular model set with 51 atoms and 50 bonds covering carbon

and 500mm focal lengths for comparative refraction experiments

Seventy-eight-piece molecular model set with 45 atoms and 33 bonds for building basic organic and inorganic structures

6-Piece Optical Lens Set, 3", Double Convex and Double Concave Base_Octagonal supporting three-rope compound arrangements forSix piece 3 inch optical lens set combining three double convex and three double concave glass lenses at 200mm, 300mm, and 500mm focal lengths for comparative refraction experiments.