The 5696 is a special quality industrial thyratron. It was designed for relay switching applications particularly in counter circuits and instruments. Typically the anode circuit impedance would be 5,000 Ω.
The RCA logo.
The g2 has extended sides that are bent into a three sided open box.
Here the g2 shape is clearer.
The anode is the thin vertical strip on the right opposite the slot in g2. In operation g2 is normally connected to the cathode.
Another view of the small vertical anode strip.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 37 mm tall.
Reference: Datasheet. Type 5696 was first introduced in 1948.