Use this Teltron tube holder as a mounting for the entire tube system needed for student experiments, such as Helmholtz coils and auxiliary coil. The tube holder with its five-pole socket allows for easy access to almost all tube connections via 4 mm-safety jacks. In addition, a cathode protection circuit is integrated in the tube holder to safeguard the hot cathode against over voltage, making the tube easy to change and operated. The Helmholtz coils can be fastened in both slots on the base of the tube holder. Each slot possesses a metric scale allowing precise adjustment of the coils up to a maximum spacing of 150 mm. The auxiliary coil can also be inserted into the stepped front side of the tube holder. Size: 13 x 19 x 25cm; weight: 1 lb.