Thick Yarn for Crocheting: you will receive 5 rolls luminous yarns,diameter: 0.2cm-0.25cm/0.08"-0.1" (Approx.),length: 50m/55yard (Approx.) Glow in the dark: Different colored threads will emit different lights, please choose according to your needs. The glowing effect relies on UV light, and if you have such a flashlight you can always recharge your yarn. If not, you can put it in the sun. Polyester Material:anyone into crochet, knitting and crafting would cherish this yarn pack since it is easy to use and beginner-friendly,soft and not easy to break. DIY ARTIST: You can use it to decorate anything you can think of, make luminous hats, scarves and hoods for nighttime adventures, or add fun embellishments to clothing to make your items look cool.