The Swiftwick Pursuit One Merino Wool Socks have a one inch tall cuff. We'd call them shorties, but not to the extent that it feels like the tiny, cuffless socks that joggers often wear. Like all their products, Swiftwick makes the Pursuit Socks in their own Tennessee facility. They use a blend of US and New Zealand sourced Merino wool and knit the socks with a high tech machine that employs 200 needles. Swiftwickknits their socks using a 200-needle 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 "four" in the name refers to the four inch cuff height. This height makes them feel great in inclement weather when a bit more coverage may keep grit and dirt from falling down into your socks as it gets thrown up from the front wheel. In addition, the taller cuff height, along with the multiple knitting patterns in the footbed and cuff, adds to the compression nature of the socks to promote blood flow in the feet and lower legs. And as you might guess, improved vascular performance means reduced fatigue and speedier recovery.The Swiftwick Pursuit Four 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.