U.S. missile and defense electronics supplier Raytheon in the near future to receive a contract for the supply Patriot air defense missile systems to Sweden.

According to a 1 August report by the Swedish radio, Sweden will sign a contract to buy the Patriot air defense missile system from U.S. arms manufacturer Raytheon this week.

Stockholm will buy four Patriot firing units and an undisclosed number of missiles, according to the report.

“There are a number of other countries that already have it and we expect the first delivery in 2021,” Swedish radio quoted Defense Minister Peter Hultqvist saying.

Sweden began talks over the purchase, initially worth around $1.13 billion, last November. The contract includes an option to buy up to 300 missiles, which would bring the final bill to around $3 billion.

According to Raytheon, the Patriot air defense system is the foundation of integrated air and missile defense for 15 nations.

Since January of 2015, Patriot has intercepted more than 100 ballistic missiles in combat operations around the world; more than 90 of those intercepts involved the low-cost Raytheon-made Guidance Enhanced Missile family of surface-to-air missiles.

Those engagements were possible because Patriot is built on a foundation of more than 3,000 ground tests and over 1,400 flight tests.

Raytheon has built more than 220 Patriot fire units and delivered them to customers in 15 nations. Many of those countries have chosen to take advantage of Patriot’s flexible architecture and upgrade their systems.