This rare and odd Hemingray is supposed to be part of Steinmayer's patented design #2,392,342 for a combined spark-gap and insulator. The patent was filed in 1943 but the insulator is dated "38:" i.e. 1940; make of this what you will. Flake on outside of inner skirt and scuffed area on dome (both pictured), otherwise mint.

$700 postpaid.