This item is a great teaching tool of physics for student, assisting teachers and parents in better physics teaching. Helping students understand physics knowledge by building series and parallel circuits, their learning experience. Features -Note: There are slight differences in appearance between batches - Color: Green. - Material: Plastic, Copper. - Size: About 8.50X3.00X2.00cm/3.34X1.18X0.79inch. - Fine workmanship, easy to install, convenient to use - Enrich children's , cultivate hands-on ability and consolidate knowledge - Great teaching tool of physics for student, assisting teachers in better physics teaching - Suitable for physical experiments, scientific experiments, summer camps, home school unit study, etc - Helping students understand physics knowledge by building series and parallel circuits, their learning experience Package list: 12 x Battery Holder