Best 866A listed at

866 / 866Jr / 866A / 866AX Mercury Rectifier (listed at top of page)

872A Mercury Rectifier (listed at bottom of page)

866/A=VT-46A Half-Wave Rectifier (Vfil=3V) - Electronluv preamp and amps - Johnson Valent 1945 - Space Tech Labs (Canada) Power Supply TO BUY 866A
1) 866A GE NOS tilted filament cylinder inside tube, tube works fine, in white box $15 1) 866A RCA NOS 1974, some flakes off of internal top plate, this occationally occurs, original box $25 (good value) 1) 866A RCA low hours/tests like new 1956, some graphite flakes off of top plate, this occurs after tube is used $20 (good value) 1) VT-46A=866A RCA used/good mid-1940's in white box $20 0) 866A Sheldon by Sal-Mar Labs New Jersey NOS original box with data sheet 1940's 1) 866A Cetron used/60% $7
872A=VT42 Mercury Rectifier 872A RCA and CEI 4 tubes @ $50 ea) 872A RCA like new 1970's 1 tube $60) 872A GE NOS 1974 original box, some carbon flaked off top cap, probaby burned off at factory since their is not 1 scratch on base, tube doesn't look to have ever been plugged into a bayonet socket