Industrial Hardware & Specialties supplies a "Free" document Distinguishing Bolts From Screws-U.S. Customs and Border Protection,This publication is intended to provide guidance and information to the trade community. It reflects the position on or interpretation of the applicable laws or regulations by U.S. Customs and Border Protection (CBP) as of the date of publication, which is shown on the front cover. It does not in any way replace or supersede those laws or regulations.