Large Needle Electroscope, 1.5lbs, 7.0x6.0x4.0 in, ideal for classroom demonstrations of electrostatic principles, A light-weight metal vane, used as a pointer in the electroscope. A transparent scale, provided to measure the angle of the deflection
Pulley Large Demonstration Double, 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