We'll admit - we're sock-nerds. So when we developed the Function 5 the goal was to create the perfect fusion between boot and sock. We worked closely with boot fitters to dial in five precisely located comfort pads that diminish pressure points for the ultimate fit. Shin padding protects from "shin bang" while Achilles padding reduces heel lift. We've even developed a pad zone that protects the top of the foot from second buckle pressure. Plus nothing feels better than the warmth Merino Wool provides when the mercury drops. And since Merino Wool is naturally antimicrobial this sock repels bacteria and odor. If you're a skier or rider with sock-nerd tendencies you'll love the attention to detail we put into this sock. Still made in Vermont. Guaranteed for life.