The xtenex elastic shoe laces present the indexed tensioning nexus elastic lace patented technology that allows to create an adjustable tensioning between shoe eyelets this technology helps to solve the lace migration issue which is the source of footwear related pain and discomfort the 50cm long xtenex laces have an elastic core and a series of knots along the length of the lace at consistent intervals more knots between eyelets mean a looser fit while less knots mean a tighter fit the knot