Heavy anti-aircraft weaponry consisted of four twin gun turrets in shielded mountings amidships. The main armament consisted of two 6 inch guns in single mountings fore and aft. Gold was used to make scabbard mountings and bracteates. Different pools require different mountings and fixtures. This enables cylinders from different manufacturers to interchange within the same mountings. This would require the MiG-17 to be fitted with bomb mountings and release mechanisms. Land mountings and all single mountings all used the single open-ring sight. There were four mountings for cylindrical fuel tanks on the fenders (two per side). This complicated the mechanical design of the turrets, particularly the quadruple mountings. It was stolen in 1804, and recovered without its Carolingian gem-studded gold mountings. The use of barbette mountings originated in ground fortifications. The nacelles were joined by an auxiliary wing whose purpose was to stabilise the mountings. The initial design called for two octuple mountings for the QF 2-pounder Mk. Two tube mountings (later on, multiple mountings) were generally found amidships. The four Bofors twin mountings were removed in 1980.