Women's Flexus Istra Winter Booties The Flexus by Spring Step Women's Istra Booties combine plush warmth and waterproof protection for effortless winter style. Crafted with a smooth waterproof microsuede upper, these cozy ankle boots feature a plush faux-fur collar accented with two decorative buttons and stretch bungee-cord details. A convenient pull-on silhouette allows for effortless wear while securing a soft, comfortable fit around the ankle. Inside, a cozy faux-fur lining and cushioned footbed surround feet in continuous warmth and soothing underfoot support. Built on a lightweight, slip-resistant polyurethane outsole with a 1 1/4-inch heel, they deliver shock-absorbing comfort and steady traction across cold, wet conditions.