fragments, a lethal (at very close range) blast overpressure and, if a surface or sub-surface burst, a useful cratering and anti-materiel effect — all in a munition much less complex than the later versions of the shrapnel shell. However, this fragmentation was often lost when shells penetrated soft ground, and because some fragments went in all directions it was a hazard to assaulting troops. Variations One item of note is the "universal shell", a type of field gun shell developed by Krupp of Germany in the early 1900s. This shell could function as either a shrapnel shell or high explosive projectile. The shell had a modified fuze, and, instead of resin as the packing between the shrapnel balls, TNT was used. When a timed fuze was set the shell functioned as a shrapnel round, ejecting the balls and igniting (not detonating) the TNT, giving a visible puff of black smoke. When allowed to impact, the TNT filling would detonate, becoming a high-explosive shell with a very large amount of low-velocity fragmentation and a milder blast. Due to its complexity it was dropped in favour of a simple high-explosive shell. During World War I the UK also used shrapnel pattern shells to carry "pots" instead of "bullets". These were incendiary shells with seven pots using a thermite compound. When World War I began the United States also had what it referred to as the "Ehrhardt high-explosive shrapnel" in its inventory. It appears to be similar to the German design, with bullets embedded in TNT rather than resin, together with a quantity of explosive in the shell nose. Douglas Hamilton mentions this shell type in passing, as "not as common as other types" in his comprehensive treatises on manufacturing shrapnel and high explosive shells of 1915 and 1916, but gives no manufacturing details. Nor does Ethan Viall in 1917. Hence the US appears to have ceased its manufacture early in the war, presumably based on the experience of other combatants. World War II era A new British streamlined shrapnel shell, Mk 3D, had been developed for BL 60 pounder gun in the early 1930s, containing 760 bullets. There was some use of shrapnel by the British in the campaigns in East and North East Africa at the beginning of the war, where 18-pdr and 4.5-in (114 mm) howitzers were used. By World War II shrapnel shells, in the strict sense of the