The W88 is a United States thermonuclear warhead, with an estimated yield of 475 kiloton (kt), and is small enough to fit on MIRVed missiles. The W88 was designed at the Los Alamos National Laboratory in the 1970s. In 1999 the director of Los Alamos who had presided over its design described it as "the most advanced U.S. nuclear warhead." The Trident II SLBM can be armed with up to 8 W88 (475 kt) warheads (Mark 5) or 8 W76 (100 kt) warheads (Mark 4), but it's limited to 4 warheads under SORT. D… (More on W88)