The Solothurn S-18/1100 20 mm Anti-Tank Cannon was a Swissanti-tank rifle used during the Second World War, and was a variant of the S-18/1000 with modifications for automatic fire. Being the first rifle between the Solothurn anti-tank rifles to have been equipped with a select-fire option, the S18-1100 was offered to some buying countries (such as Italy, Netherlands and Switzerland) as a "Universal Weapon" usable both as anti-tank and anti-aircraft weapon.
20 mm Solothurn Anti-Tank Cannon S 18-1100, AA-Mount (Museum Altes Zeughaus Solothurn, Switzerland)
As a result of its large, powerful ammunition the gun had a tremendous recoil, and its size made portability difficult. The Solothurn firearms company was owned by the German firm Rheinmetall, and used the Swiss company to manufacture arms which were prohibited for manufacture by any German firm, to get around arms limitations imposed upon them at the end of the first World War.