Concise

Concise made lots and lots of little plastic circular slide rules. Many got printed with some other corporation's logo, I guess to give away as marketing material.

Sama & Etani Science Tables and Slide Rule (Model 600, insert ST)

There's awesome power in this little thing, designed by Sama & Etani and made by Concise. At 3"x4", it's a calculator and reference manual. There's a full periodic chart on the back, and the body of the slide rule is a sleeve that houses a two-sided card with loads of math and science material. Really, it's all the crib notes a HS student could possibly need! The worn carrying case says "physics is phun". Phat.

Consise CTCS-552

These little wonders are just so cool! Too bad they don't come with magnifying lenses.

Concise Model 28

The logo is "Canadian Marconi Company".

Concise 28N

Concise Sama & Etani Model 90

Concise 250

Probably the best all-around Concise I've seen.

Concise Hope No. 740

Perfect condition.

Unknown model number

Here's another nice card-style rule. I'm not exactly sure what kind of engineer was interested in converting kinematic centistrokes to saybolts, redwoods and englers, but Concise had a reference for him.