UNTESTED Tektronix Type L Plug-In Unit Fast-Rise Calibrated Preamp ~ Made in USA

Hickok Model 1822 (Tektronix) Unit Dual-Trace WIDE BAND CALIBRATED PREAMP SEE!

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

Tektronix Type L Fast Rise Preamp Tube Vintage Oscilloscope Test Inst. Plug in

Tektronix 013-013 - Time Base Plug In Extension - Untested

tektronix type 53 / 54D high gain preamp plug-in untested

Tektronix D-150 Input Fixture for 535/540 Scopes

Tektronix Type 1A2 Plug-in - Dual Trace for Oscilloscope 500 Series