Hair rollers are made of natural PE fabric material. I do not recommend sleeping with them. Create your favorite wavy hairstyle, suitable for most hair conditions. Easy to use: Pull hair onto the roller with the hook. Remove rollers when hair is dry and spray with hairspray. How to get layered and textured hair: Apply a curl-defining cream to style hair and divide hair into several sections. Then, put the rollers in order. If you have never styled yourself before, learn the steps to place hair rollers. Practice makes perfect. Warm tips: do not disassemble the rod after assembly. If you have any questions, feel free to contact us.