Low Power Protected Tube

Ref. E4

With a total length of 7” (17 cm) and a maximum diameter of 1.75”(4.4 cm), this low power tube, probably intended for use in some portable or dental units, is well protected in its central part by a 2mm thick lead jacket around a cylinder of what looks like fiber.  

This fiber cylinder is separated from, but fixed to, the glass wall of the tube by small cushions of cork agglomerate in order to allow the free circulation of oil.

There is no type number and technical specifications remain unknown.