The Zimmerli Royal Classic Open Fly Brief 2528406 is made of single jersey knit mercerized cotton from long twisted yarn that produces a feather-light and soft material with the smoothest texture of any of Zimmerli's fabrics. Zimmerli's Royal Classic Open Fly Brief 2528406 is made with a circular knitting process that gives the fabric a four-way stretch quality that ensures a close fit and shape retention.