For those who want the lightest running sock but still want a super-fine Merino wool, the Ultra-light fits the bill. Nothing but protection between you and your running shoes. Our patented Full Contact Fit hugs the contours of your foot and stays put so there are no loose socks to rub you the wrong way. This no-show sock will not fall down into your shoe. Flat knit design for zero bulk. Fully vented top for maximum breathability. No-show height. No cushioning in the footbed.