Rubber sole Flyknit upper delivers durable, yet lightweight flexibility. fit. Synthetic overlays in high-wear areas such as the toe and lateral side enhance durability. Molded flex grooves in the forefoot allow your foot to move naturally. Flywire technology integrates into the laces at the midfoot for a dynamic fit that helps keep your foot in place without restricting natural movement. Firm rubber in the heel provides durability and stability for high-intensity intervals. The most comfortable Metcon to date, the Nike Metcon Flyknit 3 Men's Training Shoe delivers the flexible breathability of a Flyknit upper with an updated collar for comfort. Its drop-in midsole works in tandem with firm rubber in the heel to provide durability and stability for highintensity intervals.