Commercial distribution means any distribution of a device intended for human use which is held or offered for sale but does not include the following:
(1) Internal or interplant transfer of a device between establishments within the same parent, subsidiary, and/or affiliate company;
(2) Any distribution of a device intended for human use which has in effect an approved exemption for investigational use under section 520(g) of the act and part 812 of this chapter;
(3) Any distribution of a device, before the effective date of part 812 of this chapter, that was not introduced or delivered for introduction into interstate commerce for commercial distribution before May 28, 1976, and that is classified into class III under section 513(f) of the act: Provided, That the device is intended solely for investigational use, and under section 501(f)(2)(A) of the act the device is not required to have an approved premarket approval application as provided in section 515 of the act; or
(4) For foreign establishments, the distribution of any device that is neither imported nor offered for import into the United States.