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: 200 mm focal length, Lens measures 2in diameter, 0.2 weight
reflection and refraction demonstrator, 16cm diameter acrylic water tank has a 360 degree scale and a moveable arm carrying a laser activated by a push-button, Thumb screws on the side of the laser harness can be adjusted to finely position the laser beam