Texas Code of Criminal Procedure - CRIM P Art. § 18B.053. Application Requirements

(1) be made in writing under oath;

(2) include the name of the subscriber and the telephone number and location of the communication device on which the pen register, ESN reader, trap and trace device, or similar equipment will be used, to the extent that information is known or is reasonably ascertainable; and

(3) state that the installation and use of the device or equipment will likely produce information that is material to an ongoing criminal investigation.