QiYi Flash Stacking Cups (Stem) - Red is a twelve-cup sport stacking set with a quick-release stem for gathering cups between rounds. Three vent holes in each cup base bleed air out during down-stacks, cutting resistance so pyramids collapse cleanly. Durable plastic survives constant drops, and the red colour keeps your stack visible against busy mats. Standard sequences like the 3-3-3, 3-6-3 and cycle translate directly from competition formats.