Starrett bills this as an "engineer's" level. Mine was a thank-you gift from my son for helping him with a garage cleanout. I've used it several times*, and it's been way handier than taping blocks of wood under a regular level.
Mine says, in way tiny text near the scale, something like "1/16" per foot."
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*Setting up the outrigger support for a window air conditioner and then testing the unit for proper tilt; checking a subtle tilt on the rear floor of our RV. That's so far; I'm sure other occasions will arise.