 The system aims to integrate the Stunner interceptor from the jointly-funded David's Sling program with Patriot PAC-3 radars, launchers, and engagement control stations.The two-stage, multimode seeking Stunner would replace single-stage, radar-guided PAC-3 missiles produced by Lockheed Martin.Government and industry sources claim the Stunner-based PAAC-4 interceptors will offer improved operational performance at 20 percent of the $2 million unit cost of the Lockheed-built PAC-3 missiles.