XTENEX Auto Locking Laces - SS18 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 footbed. Eliminates "Dual-Compression Impact" - (impact #1 = shoe sole hits ground / impact #2 = foot hits foot bed of shoe). Enhanced Lateral Stabilisation - Is achieved by increasing the tension along the left or right side of a shoe upper. This helps to stabilise and support the foot within the footbed while enhancing footwear and foot care technologies such as orthotics, arch supports and insole technologies. Asymmetrical Lacing - The shoe upper can be moulded 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.