XTENEX X300 Series 30" Laces 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 they eyelets; increasing comfort and keeping the foot stable in the foot bed No plastic pieces are needed. Eliminates "dual-compression" impact A lace shoe is made into a slip-on - Never tie your shoe 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