Fine very rare thyratron tubes manufactured in Switzerland by renowned Brown Boveri. These thick glass tubes come with anode top cap, silvered internal components, and four pin metal and ceramic base. They are printed in red SCHLATTER SPECIAL TUBE HT3, and come with garantee & instruction sheet headed Brown Boveri Company BBC, written in German langage. Boxes are heavy duty corrugated cardboard with adequate foam padding, printed 2 JUNI 75 HT 3 LAD TUBE NO. 271/120 (variable) BROWN BOVERI.