Pulley, Triple Sheave, Pulleys wheels are made of plastic and mounted securely in an aluminum housing with a hook on both the top and bottom for suspension, Size: 50mm
Energy Tube, teaching resource for an array of scientific concepts: open and closed circuits, conductors vs. Insulators, light waves, sound waves,currents, and energy, When a conductor touches both of the electrodes on tube, tube emits a sound and flashing red/green/blue LED lights