A signaling device for a sports apparatus such as a tennis racket, a golf club, of a person or of an item of clothing of the person, for generating signals in the event of an actual movement of the signaling device, wherein the signaling device is configured to output at least one signal as a function of the actual sequence of movements, wherein the signaling device is configured such that an output of the signal occurs during the sequence of movements, so that a feedback about the actual sequence of movements occurs if necessary during the sequence of movements and wherein the signaling device is configured such that the output signal varies as a function of the actual movement at least with respect to intensity, time or frequency, characterized in that the signaling device comprises a resonance body and a holding device, wherein the resonance body and the holding device are configured to be connected to each other or to be connectable to each other, in order to fasten the resonance body to a sports apparatus via the holding device, wherein the resonance body has further a cavity for generating an acoustic signal in the event of a movement, wherein the resonance body has a single opening, which is fluidically connected to the cavity and via which the cavity is fluidically connected to the surrounding area, wherein the cavity is enclosed by a wall of the resonance body and the base of the resonance body, wherein the base is configured to be without an opening, wherein the signaling device has only parts that are not tiltable, rotatable or otherwise, relative to the surrounding area, for example not rotatable or pivotable by means of joints, bearings, wherein the resonance body is configured to be dome-shaped, wherein the opening is configured on the tip of the dome-shaped resonance body. wherein the signaling device is configured to output at least one signal as a function of the actual sequence of movements, wherein the signaling device is configured such that an output of the signal occurs during the sequence of movements, so that a feedback about the actual sequence of movements occurs if necessary during the sequence of movements and wherein the signaling device is configured such that the output signal varies as a function of the actual movement at least with respect to intensity, time or frequency, characterized in that the signaling device comprises a resonance body and a holding device, wherein the resonance body and the holding device are configured to be connected to each other or to be connectable to each other, in order to fasten the resonance body to a sports apparatus via the holding device, wherein the resonance body has further a cavity for generating an acoustic signal in the event of a movement, wherein the resonance body has a single opening, which is fluidically connected to the cavity and via which the cavity is fluidically connected to the surrounding area, wherein the cavity is enclosed by a wall of the resonance body and the base of the resonance body, wherein the base is configured to be without an opening, wherein the signaling device has only parts that are not tiltable, rotatable or otherwise, relative to the surrounding area, for example not rotatable or pivotable by means of joints, bearings, wherein the resonance body is configured to be dome-shaped, wherein the opening is configured on the tip of the dome-shaped resonance body.