Slide Rule Engineering Instruments Inc. Wooden

Slide Rule - Engineering Instruments, Inc. 250-V w/case & instructions

Vintage Slide Rule: Engineering Instruments inc 250-BT in sleeve, missing cursor

Vintage Engineering Instruments Inc Drafting Slide Rule Peru Indiana USA

Vintage Engineering Instruments inc. 250-V Simplex Slide Ruler

Vintage Engineering Instruments 10” Slide Ruler Model 250 -V

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

Engineering Instruments Inc Slide Rule Peru, Indiana USA Wood