I brought one pair of Injinjis and two other brands to the Jungle Marathon, a seven day 135 mile stage race through the Amazon rain forest. Tough terrain swamps,water crossings, heat and humidity(perfect breeding ground for foot troubles). The other socks aggravated my feet within an hour of putting them on. I ended up wearing the same pair of Injinji socks for the entire 7 days(thats right, I put them on even when they were wet and muddy). I was utterly amazed and thankful, no blisters, no pain. There is no way, I would consider wearing anything but, Injinjis for a race. I also like that there is definite left and right socks and the color choices.