Abstract: A card holder extrusion mounted on a conventional card holder located in front of a shelf. One or more cards with a hooking tongue having a pair of parallel longitudinal edges are removably mounted on the conventional card holder. This card holder extrusion includes a substantially flat body having a front face, a rear face and parallel longitudinal upper and lower edges. The flat body is fastened to a conventional card holder. A card is removably mounted in the card holder extrusion. A card holder assembly results from the combination of one card holder extrusion and at least one card. A method for removably mounting the card holder extrusion on a conventional card holder and a method for mounting and removing a card from the card holder extrusion is also disclosed.