No actual data-sheet for the QS70/20 could be found but it clearly fits into the sequence of stabilisers. The QS70/20 data-sheet is probably a reasonable guide to the operating conditions of this gas filled valve but at five volts higher burning voltage.
The details are not visible - just the mica insulators.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 45 mm tall.
Absolute Maximum Operating Conditions¶
Updated October 13, 2020. shape:thin.glass.tube construction:all.glass type:voltage.stabiliser age:1950.1960 base:b7g pins:7 pin:1.k pin:2.k pin:3.k pin:4.pa pin:5.a pin:6.a pin:7.a