The 90 mm F1 smoothbore gun is also referred to as the CN90F1 and in the past was known as the DEFA D921. It is a light gun which fires fin-stabilised projectiles and is fitted with a double-baffle muzzle brake. The breech is semi-automatic and fitted with a vertical sliding wedge breech block.

The firing mechanism is mechanical and the recoil mechanism is a single cylinder with a constant stress spring. The recuperator system is hydropneumatic. Low-angled rifling is used in the barrel.

This gun has also been produced in South Africa by LIW under the designation of the GT 2 for that country's Eland 90 (4 x 4) and Ratel 90 (6 x 6) vehicles. Prime contractor in South Africa (see entry later in this section) is the LIW Division of Denel.

Production as required.