Cal. Bus. & Prof. Code § 2539.4
(a) To the extent not inconsistent with federal law, a licensed dispensing audiologist shall, before the consummation of a sale of a hearing aid that uses proprietary programming software or locked, nonproprietary programming software, provide the purchaser with a written notice in 12-point type or larger that states the following: “The hearing aid being purchased uses proprietary or locked programming software and can only be serviced or programmed at specific facilities or locations.” The written notice shall be signed by the purchaser before the sale. The licensed dispensing audiologist shall keep and maintain a copy of the notice in accordance with Section 2539.10.
(1) For purposes of this subdivision, the following definitions apply:
(b) A licensed dispensing audiologist shall, upon the consummation of a sale of a hearing aid, deliver to the purchaser a written receipt, signed by or on behalf of the licensed dispensing audiologist, containing all of the following: