It is bulb holder for electricity teaching. It can help children to consolidate the knowledge in books and gain a deeper understanding of of current. What's more, it can improve kid's hands-on ability, thinking ability, creativity, and improvement. Features -Color: Blue. -Material: Plastic. -Size: About 7.60X4.00X0.80cm/2.99X1.57X0.31in. - It is lightweight for easy portability, so students can take the entire set outside to play with their friends. - The screw connection terminals are resistant, which the safety of the . - Durable and use. Screw type binding post for removal an installation wires quickly. - Easy and safe to use, excellent for making and breaking a single circuit. - It is great for student to learn electricity physics circuit, parallel experiments, and for classroom physics teaching use. Package list: 8 x bulb holders