[1] In 1956, the contractor Österreichische Saurer-Werke from Vienna (which was taken over by Steyr-Daimler-Puch AG in 1970) started development of an armoured personnel carrier.

[2] The next model, the 4K 2P, had a different hull layout, a new torsion bar suspension and was powered by a 250 hp Saurer 2P diesel engine.

The vehicle was succeeded in production by a new model, described in detail in a separate entry, called the 4K 7FA which uses the same automotive components as the SK-105 Kürassier light tank also manufactured by Steyr-Daimler-Puch.

[2] The gunner sits behind the driver and on the basic model has a cupola with a two-piece hatch cover opening left and right and a single day observation periscope.

A standard 0.50 inch (12.7 mm) M2 Browning machine gun is mounted on the forward part of the cupola and most vehicles are fitted with a shield to give limited frontal protection to the gunner.

The section leader is the first on the right seat and is provided with a day periscope in the forward part of the personnel compartment roof, on the right side.

[2] The suspension is of the torsion bar type with either side consisting of five dual road wheels with the drive sprocket at the front, the idler at the rear and two track-return rollers.

The weapon is provided with 100 rounds of ready use ammunition and the empty cartridge cases and links are ejected outside the turret.

This model is unarmed and has a crew of two, the driver and the medical orderly, and it can carry four sitting and two stretcher patients.

This is the basic APC with an Oerlikon Contraves 81 mm rocket launcher mounted on a turntable over the rear troop compartment.