Description
More details on associated web pages:
Ionization Gauge Tubes, Bayard-Alpert Type
Bayard-Alpert Design and Dual Tungsten or Burn-out Resistant IridiumIonization Gauge Tubes
(Catalog F27)

Bayard-Alpert Design and Dual Tungsten or Burn-out Resistant Iridium

Use this to adapt ion gauge tubes to a 2 3/4" Conflat flange.