Does your underwear have a fly? Most of our underwear styles have a standard fly, as noted below. With a fly: 18-Hour Jersey (all styles) Silver (all styles) 24/7 Woven Boxers 18-Hour Knit Boxers AIRKNIT Performance Tight WARMKNIT Long Underwear Without a fly: AIRKNITx (all styles) Stealth Tech Cashmere Long Underwear Related articles What is 18-Hour Jersey? Who is Mack Weldon? How does the underwear fit? Why are the labels on the outside of the underwear?