External BGS are available for almost any area of the body where a fracture or surgery has occurred. They are available as either units that connect to electrodes which deliver current to the skin over the non-healing bone or as a type of brace or belt that can either be worn or upon which a patient can recline when sitting. Typically, the BGS unit needs to be used for several hours a day over a three to nine month period to be effective and patient compliance is needed to ensure the best outcome. The units are relatively comfortable, lightweight and safe. They do not need adjustment, like TENs units. The electric current is imperceptible and causes no discomfort to the patient.