The .303 calibre Lewis gun was invented by US Col. IN Lewis in 1911 and saw service from 1914 to 1953. At least 202050 were built in WWI and another 152050 in WWII. The aerial mounting was invented by WO Scarff of the British army. It was manufactured in the USA and the UK. It was used by fifty different countries.
For aerial use, the aluminium tube heat sink around the barrel was removed. On 7 June 1912 the Lewis gun was the first machine gun fired from an aeroplane.
Weight 13 kg, length 1062mm for aerial use (for land use 1280mm), barrel length 670mm, width 110mm. With a 47-round magazine for land use and a 97-round magazine for aerial use.