This is an image of a Lewis Gun From WW1:
The Lewis Gun was a light weight machine gun that was developed in the United States in 1911.
Weighing at 12 kg it was a lot lighter than the Vickers Machine-Gun.
In 1915 the British Army decided to purchase the gun for use on the Western Front.
Six Lewis guns could be made in the time taken to produce one Vickers Machine gun.