After the expiration of the three-year period set forth in section 3, if a molder chooses to have all rights, title and interest in a die, mold or form transferred to the molder by operation of law, the molder shall send written notice by registered mail, return receipt requested, to an address designated in writing by the customer or, if not so designated, to the customer's last known address, indicating that the molder intends to terminate the customer's rights, title and interest in the die, mold or form by having all rights, title and interest in the die, mold or form transferred to the molder by operation of law under this act.
73 P.S. § 1880.4