A stick of delicious, nutritious WATIChew gum. According to the packaging, it's packed with "juicy Watilla goodness" and each one comes with a free sticker.
Zoë can buy some using her mobile, even though she doesn't actually like gum. It can, however, be used as a bribe to get Hiro's help in the WATI Museum.
Obtained from the candy machine at Yamashiro Station outside WATI City.