California Code, Business and Professions Code - BPC § 17509

(1) Contractual plans or arrangements complying with this paragraph under which the seller periodically provides the consumer with a form or announcement card which the consumer may use to instruct the seller not to ship the offered merchandise. Any instructions not to ship merchandise included on the form or card shall be printed in type as large as all other instructions and terms stated on the form or card. The form or card shall specify a date by which it shall be mailed by the consumer (the “mailing date”) or received by the seller (the “return date”) to prevent shipment of the offered merchandise. The seller shall mail the form or card either at least 25 days prior to the return date or at least 20 days prior to the mailing date, or provide a mailing date of at least 10 days after receipt by the consumer, except that whichever system the seller chooses for mailing the form or card, shall be calculated to afford the consumer at least 10 days in which to mail his or her form or card. The form or card shall be preaddressed to the seller so that it may serve as a postal reply card or, alternatively, the form or card shall be accompanied by a return envelope addressed to seller. Upon the membership contract or application form or on the same page and immediately adjacent to the contract or form, and in clear and conspicuous language, there shall be disclosed the material terms of the plan or arrangement including all of the following:

(2) Other contractual plans or arrangements not covered under subdivision (a), such as continuity plans, subscription arrangements, standing order arrangements, supplements, and series arrangements under which the seller periodically ships merchandise to a consumer who has consented in advance to receive that merchandise on a periodic basis.