Scale: 1/350

Set includes 24 tubs (also known as "zarebas").

Recommended for any 1/400 scale US Navy, Royal Navy, Royal Canadian Navy, US Coast Guard and US Merchant Marine World War II- and Korean War-era model ship.  Dimensions are scaled from typical 9'-5" (2.9 m) diameter tubs with a shield height of 4'-11" (1.5 m).

A set of tubs with stepped bottoms is available separately.

Dimenions of a single tub:
Outer diameter = 8.2 mm
Inner diameter = 7.6 mm
Shield height = 4.3 mm
Splinter shielding thickness = 0.3 mm
 
 © Model Monkey LLC. This 3D-printed product may not be copied or recast.

From Wikipedia: "The Oerlikon 20 mm cannon is a series of autocannons, based on an original German 20 mm Becker design that appeared very early in World War I. It was widely produced by Oerlikon Contraves and others, with various models employed by both Allied and Axis forces during World War II, and many versions still in use today.

"Just a few weeks before the Fall of France, the Oerlikon factory approved manufacture of their gun in the United Kingdom, under licence. The Royal Navy managed to smuggle out the necessary drawings and documents from Zürich. The production of the first British-made Oerlikon guns started in Ruislip, London, at the end of 1940. The first guns were delivered to the Royal Navy in March or April, 1941.

"The Oerlikon gun was installed aboard United States Navy ships from 1942, replacing the M2 Browning machine gun, which lacked range and firepower. It became famous in the naval anti-aircraft role, providing an effective defense at short ranges (in practice up to 1.5 km) at which heavier guns had difficulty tracking a target. The gun was eventually abandoned as a major anti-air weapon due to its lack of stopping power against heavy aircraft and against Japanese  kamikaze attacks during the Pacific War. It was largely superseded by the Bofors 40 mm gun and the 3"/50 Mark 22 gun. It did, however, provide a useful increase in firepower over the .50 cal machine gun when adapted and fitted to some aircraft. However, it had some problems with jamming in the ammunition feed.

"The Royal Canadian Navy popularized the use of the Oerlikon gun as an anti-ship and anti-submarine gun - while it was not effective against the armour of most larger ships, it was used extensively and effectively against U-Boats, and on the decks of larger ships. A handful of corvettes were fitted with the weapon toward the end of the war, but it appeared more commonly on frigates and destroyers at the time."