The term portee is used to describe a truck which carries a gun on its bed. The gun in question is not a permanent fixture of the vehicle and can be fired either while still within the confines of the truck bed or can be unloaded and fired in a more orthodox fashion.

The portee has the advantage of making the traditional static anti-tank gun more mobile and allows the use of fire and maneuver tactics. The portee would assume a firing position, fire at the enemy before quickly shifting to another location before its position was revealed to the enemy.

While the term portee is more often than not used to describe such vehicles used by British and Commonwealth forces during the early stages of the Second World War, the French had adopted the practice as early as 1938.

Laffly utilized their S20TL truck to mount the 25mm SA-34 anti-tank gun. These factory-built vehicles featured ramps to allow for the gun to be disembarked and also allowed the gun to fire towards the front of the vehicle or towards the rear, the latter allowing for a quick getaway after firing a shot. The windscreen was also modified to fold down to allow for a greater field of fire.

Forty of these vehicles were delivered to the French Army during the winter of 1939-40 and saw action during the attempts to repulse the Germans after they invaded.