Kizik Sydney Sneakers All White Leather Hands Free Shoes Womens 10 Flex Arc™ As the heel compresses, a quick-recovery arc flexes against the back of the midsole then pops back up for a highly responsive, highly satisfying fit. It's soft, it's secure, it's our smoothest step-in yet Dynamic Every Kizik shoe is engineered with dynamic features like our flexible, spring-back heel that snaps into place the moment you step in—just one of Handsfree Labs' more than 20 innovative technologies built for effortless movement. Durable Every Kizik style undergoes 30,000 heel compressions, to guarantee long-lasting durability and responsiveness, so you get consistent comfort and performance with every step. Innovative With over 200 patents, Handsfree Labs engineers and designers are at the forefront of footwear technology, seamlessly integrating proprietary hands-free tech into every Kizik style for unmatched convenience & innovation