Listed on page 48 in "The Exhibits of the Smithsonian Institution at the Panama-Pacific International Exposition, San Francisco, California, 1915", in section "Arts of the Northwest Coast Tribes (Tools)".

From card: "Round, thin wooden disk, slightly concave on inside, and convex on the top side which is carved - this one into two faces (human) facing each other at the hole in the center. Design covers the who surface. Brownish color, well used, in good condition (1965). These were once called Tlinkit from SE. Alaska, but 9/1962 Bill Holm of Seattle, Wash. said these were definitely Salish, and not Tlinkit. These were said to be used with spindles that held goats wool. Illus.: Hndbk. N. Amer. Ind., Vol. 7, Northwest Coast, Fig. 5a, pg. 460."