Cal. Bus. & Prof. Code § 17514
(a) A person who sends a solicitation by mail that solicits a recipient to consent to receive information via telephone, where that recipient’s telephone number is not listed on the national “do not call” registry established and maintained by the Federal Trade Commission, as described in Section 310.4(b)(1)(iii)(B) of Title 16 of the Code of Federal Regulations, shall include in the solicitation a clear and conspicuous disclosure of the following information: