The RPX 40 M 120 mm mortar carrier, designed as a private venture by LOHR Industrie, was first shown at the 1987 Satory Exhibition of Military Equipment. The vehicle shares many automotive components with the LOHR RPX 3000 light armoured vehicle. Details of this 4 × 4 Reconnaissance vehicle, also developed as a private venture by LOHR Industrie, are given in the Reconnaissance vehicles section. As of March 2001 this remained at the prototype stage.

Mounted in the rear part of the hull is a TDA MO-120-RT-61 rifled mortar firing to the rear of the vehicle. This has an elevation of +45 to +85º and can fire a PR14 high-explosive bomb to a maximum range of 8,135 m, a PRPA rocket-assisted projectile to a maximum range of 13,000 m, as well as the normal smoke, illuminating and anti-armour projectiles. Between 10 and 20 rounds of 120 mm mortar projectiles are carried.

The hull of the RPX 40 M is of all-welded steel armour plate which provides protection from small arms fire. The fully enclosed crew compartment is at the front, the engine compartment in the centre and the 120 mm mortar at the rear. The crew can enter via a door in each side of the hull and there are also two circular roof hatches between which a 7.62 mm machine gun can be mounted.

The turbocharged diesel engine is coupled to a fully automatic transmission and a two-speed transfer case.

When deployed in the firing position, the rear two roadwheels are raised so that the shock of the 120 mm mortar firing is absorbed directly by the baseplate which is in contact with the ground.

LOHR Industrie is using this as a demonstrator and it can be adapted to other types of chassis. LOHR Industrie also built the prototype of the VPX 40 M 120 mm mortar carrier based on the full tracked VPX vehicle but this is no longer being marketed. Details were given in Jane's Armour and Artillery 1999-2000 pages 586 to 587.