California Code, Public Resources Code - PRC § 42494

(1) The take-back from the consumer of a used cell phone that the retailer sold or previously sold to the consumer, at no cost to that consumer.  The retailer may require proof of purchase.

(2) The take-back of a used cell phone from a consumer who is purchasing a new cell phone from that retailer, at no cost to that consumer.

(3) If the retailer delivers a cell phone directly to a consumer in this state, the system provides the consumer, at the time of delivery, with a mechanism for the return of used cell phones for reuse, recycling, or proper disposal, at no cost to the consumer.

(4) Make information available to consumers about cell phone recycling opportunities provided by the retailer and encourage consumers to utilize those opportunities.  This information may include, but is not limited to, one or more of the following: