10-INCH SLIDE RULE MODEL 250-BT ENGINEERING INSTRUMENTS INC. PERU INDIANA 1960'S

Vintage 10 Inch Slide Rule Engineering Instruments - Model 250 BT Peru Indiana

Vintage Engineering Instruments Inc Drafting Slide Rule Peru Indiana USA

Lawrence Engineering Instruments 250-V Slide Rule Peru Indiana Vintage

Vintage Engineering Instruments Inc. Slide Rule w/ Case – Peru, Indiana USA

2 Vintage 10 Inch Slide Rules Engineering Instruments Model 250 BT Peru Indiana

Engineering Instruments Model 250-V 10 Inch Slide Rule w/Instructions & Case

Vintage 10 Inch Slide Rule Engineering Instruments - Model 250 BT Peru Indiana