The X is for cross-over. This mitten does it all. Great for powder and backcountry. Our #1 seller. SHELL: Ottoman & honeycomb Dryshell, LeatherShield reinforced palm with FlexShield. INSULATION: Tri-plex insulation system, Dryfinger II insert, SwanyDry lining. FEATURES: Uni-pull cuff, quick release strap, Precurved construction, utility heat pocket, AquaGuard lock-down zipper, Swany leash.