Grab and pack and save! 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. Super-fine Merino Wool 66% Nylon 27% Polyester 5% Lycra 2%