The US Department of State approved a sale worth nearly $2 billion of four Boeing aircraft to Japan, the Defense Security Cooperation Agency said in a press release.

“The State Department has made a determination approving a possible Foreign Military Sale to Japan for [four] KC-46A aerial refuelling aircraft and related equipment, training and support,” the release stated on Wednesday. “The estimated cost is $1.9 billion.”

Each aircraft, the release continued, will be equipped with Raytheon radar warning and GPS receivers and Northrop Grumman’s Large Aircraft Infrared Countermeasures (LAIRCM) system, among other features.

Japan continues to be an essential force for stability in the Asia-Pacific region — hence, this sale contributes to US national security interests, the release added.