Wonder Laces Shoelaces Black 37" (Fits Most Women's and Kids' Shoes) 50% polyester/50% rubber Imported No more untied shoelaces. Wonder Laces stay tied. Six times the knot strength of other laces. The only Doctor Recommended Shoelace. Flexible to reduce fatigue, cramping & soreness. More comfortable. Designed to relieve shoelace pressure and contribute to overall foot health. Ties like a regular shoelace. No funky lace locks or mechanisms. Looks like a regular shoelace, ties like a regular shoelace, but this is no regular shoelace!