Get more out of your timepiece when you wear the Caliper Slide Rule Mechanical Watch. This watch features an impressive tool: an integrated slide rule. The Slide Rule Watch allows you to quickly perform mathematical tasks such as multiplication, division, currency conversion, and unit conversion. The watch itself is purely mechanical and requires no battery. It is self-winding, so the motion of your daily activities keeps it powered. The case is milled from high-grade 316L stainless steel.