Calvin Klein Steel Micro Boxer Brief (U2719). The Calvin Klein Steel Micro Boxer Brief is like no other. The fit, feel and look of this classic Calvin Klein underwear collection set it apart from everything else. Made from an unbelievably soft stretch microfiber knit of nylon and elastane with contrast stitching. The remarkable fit and feel of the knit has made this a consistent best seller. Wide, iconic Calvin Klein microfiber logo waistband in lustrous metallic silver. Double-layer, paneled pouch for comfort and support. Seamless seat construction. Tag with size and fabric information sewn onto center back interior of waistband. Flyless.