 Without sonar or long range weapons, they utilize the surveillance capabilities of the Thales integrated mast, which integrates communication systems and two 4-faced phased arrays for air and surface search.A contract between the Royal Netherlands Navy and Damen Schelde Naval Shipbuilding in Vlissingen, the Netherlands was signed in 2007 for the construction of four vessels at a total cost of €467.8 million.The vessels resulted from the Dutch Ministry of Defence's Marinestudie.