Initially in 1920 RCA are selling the soft detector UV200 (argon gas filling) and the hard UV201 Amplifier. Both made at first by General Electric. Both tubes are operated with a filament current of 1 ampere and at 5 volts.
In 1922 General Electric replaces the bright UV201 with the dull UV201A (thoriated tungsten filament).
The original RCA logo. The internal construction is close to the earlier VT-14.
The original box. With the RC logo this is a rare find.
Thanks to Joe Gruber for sending the images.
The envelope is mm in diameter and, excluding the base pins, is mm tall.
References: 1047Joe Gruber. Type UV201 was first introduced in 1920.