The U.S. Postal Service in Wichita is now enforcing Domestic Mail Manual (DMM) 601.6.3 rule, which ensures that the delivery address in window envelopes shows completely in the window, with 1/8-inch clearance, even if the insert moves. The "tap-test" is the method used to check compliance. The mail piece is tapped on the top, bottom, right and left sides. After each tap, the delivery address must remain visible in the window with 1/8-inch clearance at all times. All WSU departments should start checking their window-enveloped mail pieces to ensure that they meet USPS requirements. Mail pieces that fail the "tap-test" may be returned to sender.
