Vintage Tektronix Type 1A1 Dual-Trace Plug-In Unit #B

Tektronix Type 3A3 Plug In, differential dual trace plug-in, untested

Tektronix Type 60 Tube Amplifier Plug In Unit - Untested

Vintage Tektronix Type CA Plug-In Unit - Dual-Trace Calibrated Preamp

1967 Tektronix Type O Plug-In Operational Amplifier 8 Tubes! For Tektronix 547

Tektronix Type D Plug In Unit High Gain Works

VINTAGE Tektronix Type 1A1 Dual-Trace Plug-In Unit

TEKTRONIX 7A13 DIFFERENTIAL COMPARATOR W/ ORG. MANUAL PLUG IN TESTED WORKING