The 6H6 in the classic glass envelope is physically the largest form of this very useful double diode. Unlike the metal version with the pressed glass foot and miniature construction, this has the old pinch construction and long connecting leads within the envelope. Also it is not screened. The metal 6H6 could work into the VHF region - the glass version could not as the capacitances were too great.
The the etched Type designation on the glass and the Raytheon name on the base.
An additional paper brand label.
Very little of the internal construction above the lower mica can be seen.
The classic envelope is 38 mm in diameter and excluding IO base pins the valve is 88 mm long.
References: Data-sheet, 3002 & 1040. Type 6H6G was first introduced in 1935. See also1935 adverts.