This disclosure relates to a hearing aid for placement on head of a user comprising a first second part. The first part may comprise an acoustic input transducer adapted to convert ambient sound picked up at the ear of the user to an electric signal, a signal processor adapted to process the electric signal according to specifications of user into a processed electric signal, and an output transducer adapted to covert the processed electric signal into a transmission signal, The second part may comprise an anchor adapted to fixate said second part under the skin to skull bone of the user, and a receiver adapted to receive the transmission signal and convert the transmission signal to an output signal perceivable as sound by the user. The first part may comprise an inner recess adapted to receive an insert element, where the insert element may comprise a first magnet adapted to in cooperation with the second part to cause the first part to attach to the head of the user.