Double Convex round Lens, Material: Glass, designed for physics and educational uses, Because of their educational use design, there may be minor imperfections that do not affect physical function, for educational uses, Size: 200mm focal length, 2in diameter and 5.5mm thick
precise project launcher, 16 mm steel balls at ranges suitable for use on the bench top or from the bench to the floor, protractor and plumb line make it easy to set any required launch angle from 45 deg downwards to straight up