SGT KNOTS Zero Gravity Style Chair Universal Replacement Lace Kit made with premium quality nylon shock (bungee) cord finished with metal stopper clips at the end of each cord. Most zero gravity style chair manufacturers use polypropylene bungee cord which does not have good abrasion and UV characteristics - resulting in the cord losing elasticity. SGT KNOTS Replacement Laces are made with ultra-premium bungee cord with an extra cover nylon cover which greatly increases durability to UV rays and abrasion. Brass stopper clips make the replacement of the original lacing much easier than using replacement cord without stopper clips.