Showing sea floor spreading with formation of crust, subduction zones, continents and mid-ocean ridges

Heavy black enamel cast iron base with plated rods, which are threaded to fit the base.

Pressed steel base with hole 10 x 1.5 mm, metric thread in the center of one short side.

RF telemetry system consists of a radio frequency transmitter and matching radio frequency receiver both operating at 433 MHz. The system is designed for the radio frequency transmission and reception. The radio frequency transmitter sends out a variable audio signal and the radio frequency receiver with built in loud speaker receives the signal. The system enables the teachers to demonstrate a variety of wave phenomenon. The system also enables the properties of the radio communications to be investigated and compared with those of visible light and other wave motions such as audible sound and water waves etc. For the operation of the system, a 9 V PP3 battery is required.

A layer of oxidized resistance wire is wound on a porcelain tube which is supported by end supports. A sliding contact and three 4 mm socket terminals are provided for use as a rheostat or as a potentiometer.Other ranges also available on request.