The zero in the name designates the cuff height as you might have guessed. These Pursuit Zero Merino Wool Socks are the shortest merino socks on offer from Swiftwick. The top of the cuff will ride just at the edge of your shoe. You don't like funky tan lines? These are the socks you've been dreaming of. Even though they basically lack the compressive double welt cuff of the taller versions, these are otherwise identical. Swiftwick makes the Pursuit Merino Socks on a 200-needle knitting machine. The benefit is that you'll get a high density, seamless sock. The process allows variability in the finished knit of the socks, as different parts meet different performance requirements. For example, the cushioned footbed gives way to the thinner, channeled upper -- both components playing a crucial role to increase your comfort. When you slip into a pair of Pursuit Socks, you'll immediately feel that they're tailored for your feet. The Y-shaped heel contour assures no bunching or overstretched feeling in the back, and the front and back of the ankle have a half-density weave that allows foot flexion and extension without bunching or tugging along the cuff of your shoe. Compared to the Aspire socks, these Merino wool socks are thicker, but just so. You won't have a problem letting out the closures on your normal shoes a bit to accommodate the extra insulation. Thanks to the wide temperature/comfort range of wool, you can wear them on chilly days when your lightweight summer socks just won't do. If it warms up during the ride, no worries -- wool breathes better than synthetics and its hydrophilic nature will ensure that your feet stay dry and comfortable. And when we say that wool absorbs less stink than most synthetic fibers, it's true. The Swiftwick Pursuit Zero Merino Wool Socks are available in Black, Coal, and Heather Grey. They come in four sizes from Small to X-Large. The multiple knitting patterns in the footbed create compression in the socks to promote blood flow in the feet. And as you might guess, improved vascular performance means reduced fatigue and speedier recovery.