Vietnam is buying six Russian Kilo class submarines, for $300 million each. The Kilos weigh 2,300 tons (surface displacement), have six torpedo tubes and a crew of 57. They are quiet, and can travel about 700 kilometers under water at a quiet speed of about five kilometers an hour. Kilos carry 18 torpedoes or SS-N-27 anti-ship missiles (with a range of 300 kilometers and launched underwater from the torpedo tubes.) The combination of quietness and cruise missiles makes Kilo very dangerous to surface ships. North Korea, China and Iran have also bought Kilos. Considering the low price, it appears that the Vietnamese boats do not have AIP (Air Independent Propulsion), which allows non-nuclear boats to stay underwater for weeks at a time.