Featuring educational, this model toy can help children develop their interest in science and their intellectual ability, innovative thinking, hands-on ability. Multifunctional feature ensures it can cultivate children's thinking ability and hobbies. It can stimulate children's interest in learning and curiosity through DIY small production, and let children understand abstract knowledge through disassembly and assembly. Made of plastic and electronic component material, it is eco-friendly and safe. The length of iron nail is 6cm. The length of battery box is 5.5cm and the width is 3.2cm. The length of switch is 4cm and the width is 2cm. Suitable for school, home, teaching accessories. Item Name: Science Experiment Electromagnet Material: Plastic,Electronic Component Battery: 2 x AA Batteries (Not Included) Suitable Age: Over 5 Years Old Features: Safe, Reliable, Creative Size Details: Battery Box: 5.5cm x 3.2cm/2.17" x 1.26" (Approx.) Switch: 4cm x 2cm/1.57" x 0.79" (Approx.) Iron Nail Length: 6cm/2.36" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Principle: When the coil is energized, the inner iron core is magnetized by the magnetic field of the wire, and the magnetized iron core also becomes a magnet, so that the magnetism of the wire is greatly increased due to the superposition of the two magnetic fields. Package Includes: 1 Set of Science Experiment Electromagnet (Including Battery Box, Switch, Sandpaper, Wire, Small Iron Piece, Compass, Enameled Wire, Iron Nail)