The set consists of 12 projectiles (six of each type) and 6 shells extra.
There are two types of projectiles in the set: high-explosive shells (HE) and armour-piercing shells (AP).
Because in 1930' the British army had only the obsolete anti-aircraft gun Pom-Pom used since Great War, they decided to get as the armament a perfect gun constructed by Swedish company Bofors. This construction seemed to be so good, that the Swedish license was bought by several countries such as Poland and the USA.
