Abstract: A device for metering flowable products, such as products in the form of powder, granules, or microspheres, usable, for example, for the preparation of treatment baths, such as baths for dyeing, comprises at least one passage for the material to be delivered, the passage leading to a diaphragm. The aforesaid diaphragm can be moved according to a vibratory motion produced, for example, by a vibrating member mounted on the device. Preferably, the diaphragm carries, associated to it, a further diaphragm, which, in conditions of fine dispensing, comes up against the first diaphragm, so as to achieve, by the effect of the common vibratory motion, an action antagonistic to the formation of aggregates or micro-aggregates in the material to be delivered.