Heintz & Kaufman Ltd.
South San Francisco, 50 Drumm Street

Producer of transmitting tubes etc. during the 30ies and 40ies. It is not "Heintz & Kaufmann" as often seen (with double n) but Heintz & Kaufman - see lables on tubes. 

Heintz & Kaufman introduced a line of transmitting tubes using a tantalum grid welded frame and tantalum anode. These tubes, identified by the trade mark Gammatron, did not require getters and could well withstand severe overloads, withouth developing gas inside the bulb. Later the trade mark Gammatron was printed also on the boxes of other conventional tubes. JAN military code was CHK.