Strategy Page
Saudi Arabia had followed the UAE (United Arab Emirates) and placed an order for THAAD (Terminal High Altitude Area Defense) anti-missile systems. The UAE ordered two THAAD batteries in 2011 after considering it since 2008. The Saudi order is for $15 billion to pay for 44 launchers, 360 THAAD missiles, seven radars and 26 fire control systems. In addition the order includes support vehicles, generators and maintenance gear plus training and tech support.
https://www.strategypage.com/htmw/htada/articles/20171031.aspx