Oerlikon Contraves 35 mm cannon are produced in several versions, the most important of which are the type KDA for anti-aircraft and ground use, the type KDB which is produced primarily for use on the twin anti-aircraft gun type GDF series mountings, the type KDC-01 which is used primarily as a naval twin mounting, the type KDC-02, a part of the NDF-C modification package and also integrated in the Oerlikon Contraves 35 mm Twin Automatic Anti-aircraft Gun GDF-003 and GDF-005, and the Type KDE which is a version produced primarily for use with gun turrets for light armoured vehicles. All these various types differ in details and weights. The type of ammunition feed varies according to the type but can be linked, belted or from a hopper.
On the 35 mm KDE, ammunition feed is selectable from either the left or right side and the time required to change from one type of ammunition to another is less than 1 second. Oerlikon Contraves has produced various ammunition feed systems for use with the KDE cannon, in the form of either magazines or automatic ammunition feeders incorporated into the turret.
In the Oerlikon Contraves system the K stands for Kanone (Cannon), D stands for 35 mm calibre and the A, B, C, E, and F stand for Type.
In production. Installed in twin KDA mounting in the German and Dutch/Belgian self-propelled anti-aircraft gun systems Gepard and Caesar. KDA also installed in British Marconi Marine, Land and Naval Systems Marksman turret, which entered production for Finland late in 1988. More recently the KDA 35 mm cannon has been installed in the Japanese Type 87 twin 35 mm self-propelled anti-aircraft gun system currently in production for the Japanese Ground Self-Defence Force based on a Type 74 MBT chassis. Type KDE, installed in the Japanese Type 89 MICV.
Twin Type KDB is installed in the GDF-001 and GDF-002 field AA systems.