I have used countless running socks, all claim to prevent blisters, provide cushioning, built to last and so on. None have fulfilled their claims. Sums do. Hands down, these are the best socks I've used. To the point I find myself in disbelief that I'm writing a review about socks with passion and determination to sway you that these are decent! After numerous ailments and rubbing in other sock providers I'd taken to taping my feet to overcome the effects of Ultra running in poor socks. Fresh out of the pack I took a pair of Sums all season socks for jaunt up some mountains. 34 miles and approximately 9 hours of mountain running later, not a single issue. Same shoes, worse terrain, longer time on feet and they performed flawlessly. Go buy some.