According to the definition given in German medical aids guidelines, medical aids are specific medical services provided by approved service providers. They include items designed to compensate for or replace impaired physical function, e.g. sight and hearing aids, prosthetics and orthopaedic equipment. All medical aids that can be provided under statutory health insurance in Germany (i.e. that are on the National Association of Statutory Insurance Funds list), are listed in the Register of Medical Devices (HMV).