This is a set of three large Abelam tridacna clam shell currency rings "yua" used primarily in bride price payments. The three are nice older examples with smooth, glossy surfaces from generations of use. All three have the notched section on the top that is a reference to the notched beak of the hornbill bird—the main totem in the area. The rings are all 19th century, range in size from 7 ½" to 9" in diameter and sell as a set for $4000. Questions?