Material: ABS + PVC + PCBattery: 3 x LR41 button batteries Crochet size (Optional): 2.5 mm/0.09", 3.0 mm/0.11", 3.5 mm/0.13", 4.0 mm/0.15",4.5 mm/0.17", 5.0 mm/0.19", 5.5 mm/0.21", 6.0 mm/0.23", 6.5 mm/0.25"Length: aprox.155 mm/6.10inchOur crochets are made of high quality ABS, PVC, PC material, safe.No matter you are knitting lover or crochet learner, this crochets is convenient and practical for you.Hooks are battery operated with a simple on/off switch. You can control it according to your will.There is different size marked on the handle to help you find which size you need clearly.The design of LED light, especially perfect for crocheting with dark colored yarn or when you just need more light to crochet by.