The Maersk E Series comprises eight 14,770 twenty-foot equivalent unit (TEU) container ships. Each sister ship bear names beginning with the letter "E". Until 2012, they were the largest container ship ever constructed, and are among the longest ships currently in use at 399 metres (1,302 ft) long and 56 metres (184 ft) wide. They are owned by the Danish A. P. Moller-Maersk Group. The first in the class built was Emma Maersk by Odense Steel Shipyard Ltd., Denmark. The E-class was followed by the Triple-E class, which is even larger and more fuel-efficient.