The shaker cup's leak-proof mechanism doesn't rely on a single rubber ring for a hard seal, but rather on a triple-layered structure: An embedded silicone valve in the lid, a spiral pressure-locking mechanism, and a micro-arc-shaped drainage groove at the rim.
When the cup is tilted, the valve automatically closes due to the pressure difference; when the lid is tightened, the rotating threads generate uniform pressure, ensuring a complete seal; and the almost invisible micro-arc groove at the rim guides condensate back rather than overflowing.
