Lace PERFORMANCE METALLIC LACE: SPARK by Derby Laces create a natural friction when tightened to help them stay tied, tight, and where you want them while skating. HARDENED PLASTIC TIPS: SPARK by Derby Laces feature a hardened plastic tip that is extremely durable. DURABLE FIBERS: SPARK by Derby Laces are braided laces made out of metallic coated durable fibers. They have a unique texture that allows them to tighten and loosen easily. SUITABLE FOR: Roller Derby Skates, Roller Skates, Hockey Skates, Speed Skates, Boots, Skates, Regular Shoes