Xtenex Features:The Xtenex Lace expands during natural foot swelling and eliminates foot compression.The lace does not slip — the knots maintain the original fit by restricting involuntary lace movement through the eyelets: increasing comfort and keeping the foot stable in the foot bed.No plastic pieces are needed.Eliminates "dual-compression impact" (impact #1 = shoe sole hits ground / impact #2 = foot hits foot bed of shoe).A lace shoe is made into a slip-on — Never tie you shoelaces again!Asymmetrical lacing — the shoe upper can be molded to the natural non-symmetric form of the foot by independently adjusting the tension between each set of eyelets. The unique ability to have different tension zones along the entire lacing system results in a custom fit every time.Enhanced lateral stabilization is achieved by increasing the tension along the left or right side of a shoe upper. This helps to stabilize and support the foot within the foot bed while enhancing footwear and foot care technologies such as orthotics, arch supports and insole technologies.