Since before the Spanish-American War the United States Navy preferred to design and build their weapon systems in-house,but sometimes that was not practicable. One
example was the medium weight and range anti-aircraft gun of World War Two. The USN had the opportunity to get battle reports from the Royal Navy on the lethality of
Luftwaffe aircraft and the performance of the British medium AA gun, the 40mm 2pdr Pompom. The USN chose to develop the 1.1-inch quadruple gun mount known as
the Chicago Piano. The system was a flop, as it was too heavy and prone to malfunction and overheating. Sweden to the rescue, in the form of the 40mm Bofors AA gun,
which was acquired and built under license from the Swedish ordnance firm.

3D Model Parts produces USN versions of the Bofers gun, with U-706 being the quadruple 40mm mount without shield. Because of weight constraints many USN
warships carried this version instead of the shielded version. Packed in a tube, set U-706 provides nine highly detailed resin gun mounts. Each mount has two parts, the
guns ad the base mount.