A slide rule, often called a slide ruler, is a rotating bezel or ring around a watch face which may be used to make mathematical calculations such as multiplication, division, etc. One of the most iconic features of a pilot and nautical watch is the slide rule bezel, made with engraved scales which let users make complex calculations on the spot without additional tools. For instance, pilots might use the slide rule to compute consumption in fuel, speed, and even distance, whereas the navigators would use it to perform tidal calculations and all other maritime measurements.
The slide rule adds functionality to the watch, making it an indispensable tool for professionals who need accuracy in calculations at any time. This feature integrates practicality with engineering ingenuity, reflecting the watch's role as a timekeeping device and a multifunctional instrument.
