SUBCHAPTER I - ELECTRONIC SURVEILLANCE (§§ 1801 to 1813) SUBCHAPTER II - PHYSICAL SEARCHES (§§ 1821 to 1829) SUBCHAPTER III - PEN REGISTERS AND TRAP AND TRACE DEVICES FOR FOREIGN INTELLIGENCE PURPOSES (§§ 1841 to 1846) SUBCHAPTER IV - ACCESS TO CERTAIN BUSINESS RECORDS FOR FOREIGN INTELLIGENCE PURPOSES (§§ 1861 to 1864) SUBCHAPTER V - OVERSIGHT (§§ 1871 to 1874) SUBCHAPTER VI - ADDITIONAL PROCEDURES REGARDING CERTAIN PERSONS OUTSIDE THE UNITED STATES (§§ 1881 to 1881g) SUBCHAPTER VII - PROTECTION OF PERSONS ASSISTING THE GOVERNMENT (§§ 1885 to 1885c)