Our coolest ruler, hands down. It’s dark blue plastic, T-shaped, and packed with information. It’s an American Wire Gauge and a screw-size gauge. It measures UTS and ISO screw pitch, has SMD capacitor info, conversion scales, transistor and diode diagrams. It has a list of SI prefixes, digital logic gates, logic identities, electrical units and abbreviations, colors and wavelengths, transmission line equations, a protractor, a breadboard and tons more. If you’re not into that stuff, use it a 13”/33cm ruler. Measures 15" x 6-1/4” x 1/16" overall, and you might need a magnifier to read some of it. Made in the USA.

It’s a cornucopia of stencils. All shapes, no alphabets. You’ll get a profusion of (8) clear acrylic stencil sheets, including: a raft of ovals; a preponderance of squares; a farrago of circles, hexagons, pentagons and triangles; a collection of a bunch of shapes, including trapezoids; a roomful of interior design shapes; a melange of electronic symbols; and an assortment we can’t altogether identify, but might be for printed circuit design. All have mm rules along at least one edge.

Vying for the Two-Really-Useful-Things-In-One Award, this 12-inch clear acrylic ruler is also a 2X magnifier! A red alignment strip runs right through the vaulted center of the ruler, which is 1-1/2” wide overall. The domed strip with the red line is about 3/4” wide. Also measures in Canadian, and at 12” long, that means 30cm.

No, these scales won’t tell you how much weight you’ve lost (you’re so disciplined!), but they will help you design something super-technical. Know why? ’Cause they’re architect’s and engineer’s scale rulers, from Helix, both (3)-sided in silver aluminum with color-coded sides. You pick: the architect’s with separate scales for 3", 1-1/2", 1", 3/4", 3/8", 3/16", 3/32" 1/2", 1/4" and 1/8" per foot, as well as a 12" ruler in 1/16" increments, all in U.S. standard; or the engineer’s, with 12", 1/10", 1/20", 1/30", 1/40", 1/50", 1/60" scales.

Says so right on the packaging. Measures (pun intended) 18” long x 1-1/2” wide. Has 1/32” increments for the first inch, then 1/16” on one edge and 0-45cm in 1mm increments on the other. Made in England of blue-tinted translucent plastic. (There is no legal penalty for using it at home or in a school.)