Tektronix Type M Plug-in Unit

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

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

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

Vintage Tektronix Type 1A1 Dual-Trace Plug-In Unit #A - as/is

Tektronix Type D Plug In Unit High Gain Works

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

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