Nike Innovation Running Knit

"With new Nike Flyknit technology, yarns and fabric variations are precisely engineered only where they are needed for a featherweight, formfitting and virtually seamless upper. With all the structure and support knitted in, the Nike Flyknit Racer's upper and tongue weigh just 34 grams (1.2 ounces). The whole shoe weighs a mere 160g (5.6 ounces) for a size 9, which is 19% lighter than the Nike Zoom Streak 3, a shoe worn by first, second and third place athletes in the men's marathon at the 2011 World Championships."