Abstract: A wall panel on a sausage encasing machine has a plurality of apertures with corresponding indicia marks indicating the direction of the apertures. The apertures match sizes of outside diameters of sausage stuffing tubes usable with the machine. This permits the operator to know that a given aperture has a corresponding given diameter. When the casing has been chosen for a sausage run on a particular machine, the operator selects a stuffing horn of a diameter that he or she believes to be appropriate for the casing being used. If a stuffing tube having a diameter of 0.576 of an inch is required, the operator takes the tube that he or she has selected and inserts it through the aperture on the machine that has a 0.576 inch indicia mark adjacent thereto. If the stuffing tube in the operator's hands is loose in the aperture selected, or if it will not even go into the aperture selected, the operator will know immediately that the wrong stuffing tube has been selected.