Manufacturers generally recommend changing the string after about 30 minutes of play time, or if the string becomes frayed. Non-bearing yo-yos will wear out the string quicker. MagicYoyo yo yo String Multi-color, 10 Pieces, 25 Pieces,100 Pieces optional Features: Made of 100% polyester material, durable and comfortable. Rainbow color. Compatible with clothing, dress, home textiles, diy decoration, etc. Yo-yo string should be changed periodically if the string becomes frayed. Description: Material: polyester Length: 41.34 inches/ 105 cm Quantity: 25 Pieces, Product weight: 60 g Color: green, yellow, orange, blue, white Alternative For use under adult supervision. MAGICYOYO: MAGICYOYO is a yoyo brand belong to ShenzhenTND Elec co.,ltd (Part of GT Int Group), a toy manufacturing professional in xhand area. Established in the year 2004, now having had about 7 years toy experience, we can assure you best services, superior quality and we're major in professional yoyo with aluminum body. In the year 2006, we get our own brand "TND" , "Ghost Hand","MAGICYOYO".we have decided to develop our own designs under our brand with the hope to provide better products to satisfy the market's needs.