The Peacekeepers (MX) are out of service. The last one was retired this year but all 50 are being stored indefinitely. They used to be armed with 10 W-87 Warheads with a yield of 300 kilotons per warhead. The 500 W-87 warheads will now arm our 500 Minuteman III ICBM's with one warhead per missile. The W-87 can be upgraded to 475 kliotons by putting an uranium tamper on the second stage.