I believe this pinback dates to the 1890s, advertising wool soap made by Wool Swift & Co. There were a few different later iterations of this one made, but I really love the single color, two word text, and relative strangeness of this one, seemingly with one girl (sans pants) admiring the woolen top of the other.
7/8" in diameter. A little age toning and a tiny dark spot on one child's eye, but overall good condition.