An NSA is a customized contract between USPS and a specific entity- often a mailer or foreign postal operator-typically lasting a year or more. NSAs provide customer-specific rates-generally lower prices on specific mail products-in exchange for meeting volume targets and mail preparation requirements. The goal of these agreements is generally to encourage additional mail volume and revenue. For example, an NSA may provide a postage rate discount, paid to the mailer as a rebate at the end of a fiscal year, for all mail volume above a specific threshold.