Abstract: A flow meter, such as is used in warm water heating systems, has a measuring element (2) with a flow-responsive element and a display element (3) with a transparent inspection glass or tube (10) with a bore in which an an end of an indicator rod (6) moves. The indicator rod is part of, or is coupled to, the flow-responsive element and it has a pointer (8) near the end inside the inspection tube. The inspection tube preferably has no markings: instead, around the inspection tube is a scale support (16) with scale markings calibrated to the positions of the pointer (8) to show the amount of flow. The scale support is essentially sleeves-shaped, with a lateral cutout (18) which permits the user to view the pointer inside the inspection tube. The scale markings may be on cut surfaces (20) adjoining the lateral cutout.