The 6BV8 is a double diode triode with each section having a separate cathode. The design use was as a synchronous detector and chrominance amplifier in colour television receivers. It is also suited to the application in sound receivers of FM demodulation and first AF amplifier.
Pinnacle were resellers and this exhibit is an import with the make designated as 'Foreign'.
The etched lettering on the glass says USA - so clearly not a cheap copy.
The three sections with the triode on the right. The busbars above the base link the three separate heaters in parallel.
The triode with copper grid supports.
The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 48 mm tall.
Reference: Data-sheet. Type 6BV8 was first introduced in 1955.