Actual design of this stamp is not significant from the standpoint of history or culture or athletics. Rather, the design supports a stamp issued to cover the rate for mailers utilizing the four-digit add-on for the addressee's ZIP code (Zip + 4). This class of mail normally is used by businesses which want the speed of delivery of that class of mail, but also dispatch enough mail at one time to qualify for the service. This is a permit-only mail service, which may also be "franked" by printed indicia. Mailers have found, however, a significant increase in positive response to mail on which a stamp is placed in contrast mail franked by indicia. Studies have shown that the general public tends to view mail with a printed indicia as "junk mail" rather than anything significant.