Project your measurements onto a screen for a large group to see with this well-made electroscope. Its cylindrical metal case has two parallel plane glass windows, both removable, through which you can shine a light for projection. Close fittings and quality materials insulate the leaf system so it stays charged for several days in dry weather. The case is mounted on a heavy metal base. The Precision Projection Electroscope comes complete. A metal cap is provided for shielding the projecting rod and knob, as well as a 3.5 cm. square piece of gold leaf. Includes instructions and experiments for use in projection or for direct viewing Size : 23 cm high case is 12 cm. diameter x 6 cm. thick.