A hearing aid device (10, 44) comprising: a hearing aid device housing to be arranged behind the ear of a user, the hearing aid device (10, 44) including an input transducer, a signal processor adapted to process signal from the input transducer to compensate for the user's hearing loss, a hearing device connector (12, 46), and wherein the hearing device connector comprises a slot a detachable speaker unit comprising: a connector part (14, 24, 34), the connector part of the detachable speaker unit comprises a tab mating the slot, the connector part comprising a plurality of contact regions and the hearing device connector comprises a corresponding number of connector arms, wherein the tab projects from the connector, a connecting element (20, 32) having an electrically conductive member, the connecting element (20, 32) connected to the connector part (14, 24, 34), a speaker unit housing configured to be positioned at least partly in the ear canal of the user, an output transducer included in the speaker unit housing, the output transducer being configured to provide an acoustic signal based on the processed signal from the signal processor, the speaker unit housing being connected to the connecting element (20, 32), a memory unit (22, 68) arranged in the connector part (14, 24, 34), the memory unit (22, 68) stores microphone data, output transducer-size, and output transducer calibration data, wherein the detachable speaker unit further comprises a microphone. a hearing aid device housing to be arranged behind the ear of a user, the hearing aid device (10, 44) including an input transducer, a signal processor adapted to process signal from the input transducer to compensate for the user's hearing loss, a hearing device connector (12, 46), and wherein the hearing device connector comprises a slot a detachable speaker unit comprising: a connector part (14, 24, 34), the connector part of the detachable speaker unit comprises a tab mating the slot, the connector part comprising a plurality of contact regions and the hearing device connector comprises a corresponding number of connector arms, wherein the tab projects from the connector, a connecting element (20, 32) having an electrically conductive member, the connecting element (20, 32) connected to the connector part (14, 24, 34), a connector part (14, 24, 34), the connector part of the detachable speaker unit comprises a tab mating the slot, the connector part comprising a plurality of contact regions and the hearing device connector comprises a corresponding number of connector arms, wherein the tab projects from the connector, a connecting element (20, 32) having an electrically conductive member, the connecting element (20, 32) connected to the connector part (14, 24, 34), a speaker unit housing configured to be positioned at least partly in the ear canal of the user, an output transducer included in the speaker unit housing, the output transducer being configured to provide an acoustic signal based on the processed signal from the signal processor, the speaker unit housing being connected to the connecting element (20, 32), a memory unit (22, 68) arranged in the connector part (14, 24, 34), the memory unit (22, 68) stores microphone data, output transducer-size, and output transducer calibration data, wherein the detachable speaker unit further comprises a microphone.