The Cha Hai, "fair cup" in English, is a vessel into which one decants the tea after infusion. It is traditionally used in China in the gong fu method of tea preparation. The tea is infused in a gaiwan or Yixing teapot and poured directly into the Cha Hai which is then used to serve the tea. As a result, each person gets tea that is infused to the same strength.
The Cha Hai can be made of glass, Yixing clay, porcelain or china depending upon the vessel used to infuse the tea.