What kind of containers are there? What's a T.E.U. and an F.E.U.?

The twenty-foot equivalent unit (often TEU or teu) is an inexact unit of cargo capacity often used to describe the capacity of container ships and container terminals. 

Forty foot equivalent unit it's a unit for measuring goods transported on ships in containers (=very large metal boxes). One FEU is equal to 25 metric tonsor 72 cubic metres.