The U.S. Navy awarded a $3.2 billion contract Friday for Bath Iron Works to produce seven Aegis destroyers during the next four years.

The contract has been expected since the Navy agreed in June to a work swap between Bath Iron Works and two southern shipyards.

Under that deal, the Bath shipyard agreed to give up work on amphibious transport ships in exchange for more work on the DDG-51 Arleigh Burke class destroyers.

Sen. Olympia Snowe said the contract provides an “unprecedented level” of stability for the shipyard and its workers, and economies of scale for taxpayers and the company.

The Navy also awarded a $1.9 billion contract Friday to Ingalls Shipbuilding in Mississippi for construction of four DDG-51 destroyers.