The 866A or VT-46A is a half-wave mercury vapor rectifier developed by RCA. General Electric (GL-866) and Amperex (AX-866) made their versions. The 866A/866 as shown in the first example was supposed to be the final version of this tube.

Length = 6.63" Diameter = 2.44"
Max voltage = 10000 PIV
Max current = 1 amp
Fil voltage = 2.5
Fil current = 5 amps         GOTO INDEX