In yap what do they use for money?

In Yap, a group of islands in Micronesia, traditional currency consists of large stone disks called "Rai." These stones, made of limestone and varying in size, are often too large to be moved easily, so ownership is typically transferred through oral agreements. The value of each Rai is determined by its size, craftsmanship, and history. Although modern currency is also used, Rai still holds cultural significance and is occasionally used in important transactions.