A northeast Iowa business that specializes in keeping your feet comfortable is celebrating 100 years in business. Fox River Mills in Osage has been knitting footwear for industries focused on people with active feet, making a variety of things from sports shoots to hiking boots.Fox River V-P Gene Oeschger says the company has been in Osage since 1971, but it was founded in Wisconsin a century ago.Oeschger says the company pioneered important technology — like making socks that don’t create blisters and “foot-specific” socks.Over three-hundred people are employed at the sock-making factory in Osage.