This paper linear slide rule was designed to assist architects and construction workers with computing the strength of steel beams. There are seven scales: A, safe load in pounds per square foot; B, ...

So first of all, yes, the Pivot X is a ruler. When folded up, it can be used to measure items or draw lines up to 7 cm (2.8 inches) in length. Extending its fold-out arm boosts that figure to 12 ...