Intricate technical drawings of vintage optometry equipment fill a black ground, with the central phoropter flanked by an array of lenses, frames, and diagnostic instruments rendered in fine white line work. The composition evokes a patent diagram, dense with mechanical detail and labeled with period typography that reads "OPTOMETRY" across the top. Built from double-wall stainless steel and made to order, holding 20 ounces with a snap-on lid, a standard-cup-holder fit, and wraparound artwork. Your commute carrying original art instead of another branded tumbler.