The Lewis gun is a First World War–era light machine gun. Designed privately in the United States though not adopted there, the design was finalised and mass-produced in the United Kingdom, and widely used by troops of the British Empire during the war.
The Vickers machine gun was based on the successful Maxim gun of the late 19th century. After purchasing the Maxim company outright in 1896, Vickers took the design of the Maxim gun and improved it, inverting the mechanism as well as reducing its weight by lightening and simplifying the action and using high strength alloys for certain components.
The QF 1 pounder, universally known as the pom-pom due to the sound of its discharge, was a 37 mm British autocannon, the first of its type in the world. It was used by several countries initially as an infantry gun and later as a light anti-aircraft gun.
The QF 3-inch 20 cwt was a common anti-aircraft gun on British warships in World War I. Britain entered World War I with no anti-aircraft artillery. The Navy provided the initial 3-inch guns from its warships for the defence of key installations.
The Ordnance QF 18-pounder, was the standard British Empire field gun of the First World War era. It formed the backbone of the Royal Field Artillery during the war, and was produced in large numbers. It was used by British Forces in all the main theatres.