Polo Ralph Lauren Stretch Classic Fit Support Knit Boxers - 3 Pack (NWSBP3). The Polo Ralph Lauren Stretch Classic Fit Support Knit Boxers - 3 Pack NWSBP3 offers optimal support and comfort with the covered elastic waistband, button fly, flatlock seams, and classic styling. Boxer is tagless. Polo Ralph Lauren's Stretch Classic Fit Support Knit Boxers - 3 Pack is made of cotton/polyester/spandex/rubber.