Pack includes [5] yo-yo replacement strings in [5] different colors - Red, Orange, Yellow, Green and Blue. This is the perfect replacement string for Duncan series of plastic and metal yo-yos. Easy to replace, this 5-pack of replacement cotton string is essential for yo-yo enthusiasts who often wear-out the string due to repeated usage. here are many types of yo-yo strings but the 100% cotton strings are considered the softest and have impressive resistance to wear & tear. Cotton strings like these are least likely to burn or scrape-against the skin.