The availability of US weapons and designs under the MDA led to the cancellation of several research projects. Indigo Hammer and the smaller Pixie were warheads intended for use with the Red Duster and Seaslug surface-to-air missiles; a British version of the US W44 was chosen instead. Blue Peacock, a atomic demolition munition (ADMs) based on Blue Danube, was cancelled in 1958 in favour of the lighter Violet Mist, based on Red Beard. The development of the even smaller and lighter US ADMs led to its cancellation as well in 1961. The US Medium Atomic Demolition Munition with the W45 was acquired instead. Yellow Anvil was a British artillery warhead. It was cancelled in 1958, and the US supplied the British Army of the Rhine (BAOR) with 36 W33 nuclear warheads that equipped four batteries of eight-inch M115 howitzers. These were later replaced by M110 howitzers.