Hot days demand a cool wardrobe. Less is more this time of year - especially when it comes to your underwear. Mack Weldon spent over a year developing their own signature fabric: 18 Hour Jersey. Cool to the touch, this fabric is a blend of cotton and modal that feels great all year long. Boxer Brief guys, try a Trunk or Brief when the mercury rises - guaranteed to keep you cooler. Pair them with their No-Show socks and you might actually need a sweater.