California Code, Penal Code - PEN § 635

(a) Every person who manufactures, assembles, sells, offers for sale, advertises for sale, possesses, transports, imports, or furnishes to another any device which is primarily or exclusively designed or intended for eavesdropping upon the communication of another, or any device which is primarily or exclusively designed or intended for the unauthorized interception or reception of communications between cellular radio telephones or between a cellular radio telephone and a landline telephone in violation of Section 632.5, or communications between cordless telephones or between a cordless telephone and a landline telephone in violation of Section 632.6, shall be punished by a fine not exceeding two thousand five hundred dollars ($2,500), by imprisonment in the county jail not exceeding one year, or in the state prison, or by both that fine and imprisonment. If the person has previously been convicted of a violation of this section, the person shall be punished by a fine not exceeding ten thousand dollars ($10,000), by imprisonment in the county jail not exceeding one year, or in the state prison, or by both that fine and imprisonment.

(b) This section does not apply to either of the following: