Whether it’s a chilly winter morning or bluebird spring afternoon, it’s always easier to get after one more lap when you’re comfortable. PhD® Nordic socks were designed with that long-distance comfort in mind, from mesh zones for ventilation to strategic cushioning in the toe and heel that provides extra padding without sacrificing boot fit. We've added Indestructawool™ Technology in high impact zones to increase durability, without the bulk. You'll also get a secure fit above and below the heel, under the arch and across the instep thanks to the 4 Degree™ Elite fit system. So keep on moving, because we’ve got comfort covered.