Depending on most sources, the S-400 is considered superior to the MIM-104 Patriot anti-aircraft missile system of the NATO. For example it has twice the range than the Patriot. However these statements were never officially proven, by any reliable source. Especially the maximum detection range of the S-400, of about 400 km, remains unproven. The newly developed 40N6 missile, for the S-400, which is expected to have this range, is still not in service with the Russian Air Force, even though this was announced multiple times by the Russian Air Force.