Pin-head munitions, also referred to as "hot-dust" by Ultras, were a family of devices revolving around the use of microscopic amounts of magnetically-contained antimatter as an explosive. A type of hot-dust was used by the True Path, a Resurgam insurgency group, which possessed a yield of two kilotons yet was said to fit into a tooth. Circa 2546, they had been outlawed for so long that some believed such creations were simply infeasible.