Russia will finally, after many years of delays, deploy its S400 anti-aircraft missile system. Roughly comparable to the latest U.S. Patriot systems, the S400 was supposed to enter service five years ago. But money, and technical, problems kept delaying things. The main feature of the S400 (compared to the earlier S300) is its search radar, which has a maximum range of 500 kilometers. The S400 will use five different missiles, depending on range (from 40-400 kilometers) and target type. Altitude of engagement ranges from 20-90,000 feet. In the West, the S400 is often referred to as the SA20. Russia expects to export the S400, and is stressing the systems ability to hit ballistic missiles and stealthy aircraft.