(!) (BEST PAIR) 5727=2D21 RCA NOS 1958 (1 pair)

2D21=5727 US Brands NOS:

4) GE

3) RCA

2) Sylvania

4) GE branded WL-2D21 Westinghouse

1) Tungsol

1) Dumont by GE

(2D21 is a miniature 2050, Vfil=6.3V @ 600ma, 1.3Kv PIV, 100ma max)
(USES: delay, grid-controlled rectifier, pulse-modulator use, also broadband
noise generator, developed in 1944) (argon gas)