Tube holder to support all S series (student) electron tubes for easy and safe operation. The five pin sockets for the tube are concealed inside the tube holder. A cathode protection switch is integrated into the tube holder, to protect the heated cathode from excessive voltage.
Dry Field Mapping Kit, includes cork-covered base, 30cmx26cm; pad of 25 sheets pre-printed conductive paper 28cmx21.5cm; pad of 100 sheets preprinted paper for drawing fields; ten metal-headed push pins; a silver conductive pen