Function: 1 Lightweight and portable, the electromagnetic induction spiral coil is specialized in electromagnetic induction phenomenon, convenient to carry and use. 2. Easy to use, can be used with stick magnets, ammeters, sliding baristers and other equipment. 3 Physical laboratory aid tools make learning of physical experiments more efficient. 4 Sturdy and durable, made of enameled copper, wear resistant, not easy to damage, long service life. 5 It is designed to demonstrate electromagnetic induction and validate the Law of Rentz for students. Great for physical education. How to Use: Specifications: a>Item Type: Electromagnetic Induction Coil Material: PVC + Brass Purpose: Physical experiments in Middle School and High Schools Applicable experiments: Study electromagnetic induction, test the law of rentz, and the outer diameter of the hole on the bottom of the coil of the coil of the magnetic induction is as follows: 40mm / 1.6in The inner diameter of the hole at the bottom of the original coil is: 25mm / 1.0in Height of round hole at bottom of original coil: approx. The diameter of the hole at the bottom of the secondary coil is as follows: Inner diameter of the round hole at the bottom of the 25mm / 1.0in secondary coil is: 15mm / 0.6in round hole at bottom of secondary coil: approx. 80mm / 3.1in Soft Core Length: Approx. 85mm /3.3" Usage: 1 Electromagnetic Induction Studies: Connect both ends of secondary coil B to two terminals of the ammeter with wire. If you use one end of the magnetic rod to quickly insert (or pull) a secondary coil, p