GRASS Instruments Polygraph Low Level DC Pre-Amplifier 7P1FL UNTESTED

GRASS Instruments Polygraph Low Level DC Pre-Amplifier 7P1G UNTESTED

GRASS Instruments Polygraph Low Level DC Pre-Amplifier 7P1J UNTESTED

VINTAGE Grass Instruments LM4 Lesion Maker / electronics Sci Fi Prop Mid Century

GRASS Instruments Polygraph Low Level DC Pre-Amplifier 7P1F UNTESTED

Grass Instruments FT03C Force-Displacement Transducer W/ Case & Multiple Springs

Vintage Grass Instruments Lab Equipment: Polygraph 1DAG DC Amplifier & 7P1G Pre-

Grass Instruments Polygraph DC Driver Amplifier P511 A.C./ Pre-Amplifier Part S2