(1) Tested Zytron 5U8 Tube Date Code 709 Triode Pentode Tube

(1) Tested Tung Sol 5U8 Tube with Box Date Code NC1 Triode Pentode Tube

(1) Tested Tung-Sol 6AW8A Tube Date Code PRI 6AW8 A High Mu Triode Pentode

(1) Tested Tung Sol 6AC7 Tube Date Code 540-3 Sharp Cutoff Metal Pentode Tube

(1) Tested Tung-Sol 12SG7 Tube Date Code MR3 Tung Sol Remote Cutoff Pentode Tube

(1) Tested Tung Sol 6X8 Tube with Box Code KR3 Triode Pentode Converter Tube

(1) Tested Tung-Sol 6SG7 Tube Date Code DP3 Tung Sol 6SG7 Remote Cutoff Pentode

(1) Tested Strong Tung-Sol 6AG7 Tube Date Code 235 Tung Sol Power Pentode Tube