Traditionally the special insignia of a minor basilica have been the "conopeum" and the "tintinnabulum." The former is a large umbrella composed of alternate red and yellow silk stripes. The latter is a bell mounted on a pole. Both were used in ancient times in papal cavalcades to the stational churches.

The umbrella was used as protection against inclement weather; the bell was used to marshal the procession and to signal its approach. Customarily these insignia are displayed in the sanctuary of the church. They are also carried in processions after the processional cross, the basilica bell preceding the umbrella or "ombrellone."

The umbrella was fabricated by Annibale Gammarelli, Rome, Italy. The tintinnabulum (bell) and the Papal Coat of Arms for the exterior of St. Mary Basilica were crafted by F.C. Ziegler Company, Tulsa, Oklahoma.

Source: The Catholic Liturgical Library website.

Related
The Coat of Arms of St. Mary Basilica
Inaugurating a New Basilica
Papal Coat of Arms