Mexico’s Most Popular Men’s Underwear Your underwear drawer is about to go next-level. Jam is one of Mexico’s most successful men’s underwear brands; a line equally inspired by pop music, pop colors, and what the designers refer to as “handsome elegance.” This collection of briefs and boxer-briefs highlights exactly what they do best, combining slick patterns and thoughtful motifs with a fit that’s superiorly comfortable and guaranteed to leave you feeling confident and carefree. This is your jam.