• Manufactured at Blackburn in 2nd Week of April in 1961.

•  Tested NOS by TV7 7D/U: 94/ 50 Baseline.

•   Gray Ribbed Plate 
  
•  Top O Getter
  
• Chrome Dome
• Cross Top
• Date Code: kM1 B1D2

Testing & Condition

• Minimum reading: 65% (per original 50 baseline; military standard).
• Tubes test NOS and meet or exceed published GM data.
• All tubes tested for gas, shorts, transconductance, and emissions.
• TV-7 tested (calibrated, military-standard tester). 

About NOS & Testing

• NOS tubes fall within the GM range published in the RCA Receiving Tube Manual; variation above/below average is normal.
• No universal test result defines NOS. Typically, NOS tubes measure between average and maximum micromhos.
• Different testers (even identical models) may produce different readings.
• 100% meter readings are not required?passing = meeting spec range or minimum (TV-7: ~65%).
• Minimum: 50 NOS: 75+