The Harpoon is an all-weather, over-the-horizon, anti-ship missile developed and manufactured by McDonnell Douglas (now Boeing Defense, Space & Security). The AGM-84E Standoff Land Attack Missile (SLAM) and later AGM-84H/K SLAM-ER (Standoff Land Attack Missile – Expanded Response) are cruise missile variants. The regular Harpoon uses active radar homing and flies just above the water to evade defenses. The missile can be launched from: