Simple Gongdaobei

Gong Dao Bei literally means "fairness cup" as Gong Dao 公道 literally means "fair, just" and Bei 杯 simply means "cup".
The reasoning behind this name is that by pouring the tea from the brewing vessel into the gongdaobei it will even out making every cup taste the same as the first and last tea to come out of the pot will have a different strength. It is sometimes also called Cha Hai.