(!!!!) (Best Pair) 201A Silvertone Balloon NOS and like new 1930 era (4.2ma and 5.0ma) (Highest mA and Gm)
(!!!) 201A Silvertone Balloon NOS 1930 era (1.8ma and Gm=500)
UX-201-A RCA Radiotron Balloon tests like new 1930's (read review)
