The markings on the shaker cup are not arbitrary; they are based on a dual calibration of hydrostatics and the volume of a single human intake.
International fitness nutrition standards typically recommend a single protein intake of 20–30 grams, corresponding to a liquid volume of approximately 250–350 ml-this range is precisely the core area of the main markings on a professional shaker cup.
The cup body features a vertically equidistant design with angled parallax compensation, ensuring the liquid level accurately aligns with the markings even when tilted at a 45° angle. The slightly curved inner wall reduces residue buildup, and the spiral flow channel enhances dissolution efficiency. These details together create a triple functional loop of "visually readable, pourable, and evenly mixed" results.
