The W76 is an American thermonuclear warhead, designed for use on the UGM-96 Trident I submarine-launched ballistic missiles (SLBMs) and subsequently moved to the UGM-133 Trident II as Trident I was phased out of service. The first variant, the W76 mod 0 (W76-0) was manufactured from 1978 to 1987, and was gradually replaced by the W76 mod 1 (W76-1) between 2008 and 2018, completely replacing the Mod 0 in the active stockpile. In 2018 it was announced that some Mod 1 warheads would be converted to a new low-yield W76 mod 2 (W76-2) version. The first Mod 2 warheads were deployed in late 2019.