A portscreen is a tablet that holds applications and can receive comms and news.
Most Earthens use portscreens as a way to search through media or do schoolwork, as Peony had mentioned to Cinder when her portscreen was broken. Many applications are downloadable, including celebrity apps and education apps, which Peony had installed. Portscreens, like most technology today, have a limited capacity and efficiency. When Cinder was fixing Peony's portscreen, she had said not to download any celebrity apps, implying that doing so may slow down the portscreen.
Portscreens on Earth are a widely-owned technology, though they are not often used on Luna, for portscreens do not display a person's glamour in a photograph, which is something Levana despises. Portscreens also have the ability to transfer currency from account to account, for example when Cinder had been purchasing items at a shop.