This auction is for 2 pcs new, NOS JAN-5687WB General Electric, made in USA with black plates. They come in very safe military foam boxes. On glass on both tubes is printed 81-03 and 83-52 33173.
Tested on my valve characteristic meter AVO Mark 4.
Those tubes are quite matched:
Tube1: Ia1=14,5mA gm1=5,0mA/V Ia2=15,2mA gm2=5,0mA/V
Tube2: Ia1=13,2mA gm1=5,0mA/V Ia2=13,4mA gm2=4,8mA/V
Due to russian war in Ukrain I will not ship to Russia or Belarus
Registered shipping worldwide is 14 usd.