Prudentius describes it in Peristephanon (x., 1066 ff.): the priest of the Mother, clad in a toga worn cinctu Gabino, with golden crown and fillets on his head, takes his place in a trench covered by a.
The Pharaoh's characteristic crown (or crowns) symbolized his royal domains, the sacred uraeus marked his divine ancestry, and he sometimes appeared in the costume of the gods with their fillets adorned with double feathers and horns.
Delphi also contained the "Omphalos," a sacred stone bound with fillets, supposed to mark the centre of the earth.
The fillets are placed on an endless chain which moves slowly through the furnace, returning underneath.
The result is that so long as the fillets are hot they are kept from contact with the air and blackening of the metal is prevented.