Elipse shaped rubber with a flattened surface.
From Nuri, Pyramid XXIV F.D. "SW" corner. 1918: Excavated by the Harvard University-Museum of Fine Arts Expedition; assigned to the MFA in the division of finds by the government of Sudan.
Harvard University—Boston Museum of Fine Arts Expedition
Nubian, Napatan Period, reign of Queen Nasalsa, 593–568 B.C.