The Check 21 Act enabled banks to send checks electronically, rather than as a paper check, to banks they have agreements with. If there are no agreements, the banks may send a substitute check, which is a new type of paper instrument, which is the equivalent of a paper check. As a result of these system improvements, the nation's interbank check-collection processes have become almost entirely electronic. Thus, the reserve banks have been able to reduce the number of their paper-check processing offices from 45 in 2003 to a single office in 2010.