In 2003, Congress passed the Check Clearing for the 21st Century Act (Check 21), which was designed to enhance payment system efficiency by reducing legal impediments to processing checks electronically. Check 21 facilitated processing checks electronically by creating a new type of paper instrument, called a substitute check, which is the legal equivalent of the original check for all purposes. Check 21 created substitute-check warranties, an indemnity, and consumer expedited-recredit procedures. Check 21 was implemented in Subpart D of Regulation CC.