Galilean sights are low-powered glass aiming sights which do not require a tube, unlike scopes. They are capable of magnifying targets at up to 3x in a compact package. British forces used galilean sights extensively during the Great War, but they came into disuse until American studies in the 1950s identified vision as the primary limited of infantry accuracy at long range. Most of these are still manufactured within Britain and exported abroad, owing to their overdeveloped lens industry.