XTENEX No Tie Shoelaces Elastic Shoe Laces XH200 100% polyester HIGHEST QUALITY PATENTED TECHNOLOGY - Rubber core covered in durable moisture resistant fabric. Will outlast your shoes! The flexibility of stretch, strength, stability, and security. XTENEX ACCUFIT works for any eyelet size 3-4 mm (standard eyelet size). Versatility: works on a wide variety of shoe designs - running, tennis, biking, hiking boots, dress shoes, snow boots, and more! UNIQUE LACE MEMORY AND EXPANSION - Elastic flexible knots disappear when you stretch the lace, allowing you to thread through eyelets. Release tension and the knots reappear. XTENEX ACCUFIT collapsible knots hold each section of lacing in place, maintaining the exact setting you create. CREATE A CUSTOM ERGONOMIC FIT - The unique ability to create different tension zones along the entire lacing system. Molded to the non-symmetric form of the foot. Custom fit stays in place every time. XTENEX ACCUFIT resolves the problem of lace migration (no more problem with lower laces loosening and a single tension point at the top of the laces). No more over tightening your laces to keep the fit firm for a run! ENHANCE AND OPTIMIZE PERFORMANCE - Maximize your shoes foot support, fit, comfort, and function. Foot care technologies such as orthopedics, arch supports, and insole products hold in place better. XTENEX ACCUFIT allows comfortable foot expansion and contraction with temperature changes. Reduces impacts, hot spots, slippage, rubbing, and crowding in the toe box.