SynchroKnit® patented contour knit creates an unrivaled precise fit. Products made with CiCLO(R) fibers reduce the persistence of plastic microfiber pollution in oceans and plastic accumulation in landfills. Double "Y" heel gore provides most precise heel fit. The yarn that we use is space dyed so there is a randomized pattern of several colors along the strand of yarn. As the sock knits in rounds or courses, the colors of the yarn will line up in varying patterns making each sock unique.