Feature: 1. 2.5MM BRASS CORE: This induction coil kit is composed of 2.5mm brass core, which can be heated to a high temperature of 1200 ℃. The most commonly used prefabricated coil comes with a storage tool box, which you can carry with you anytime you go out to work while keeping your studio neat and orderly. 2. 4 COIL KITS: 4 coils include 0.79in (20mm), 1.18in (30mm), 1.57in(40mm) diameter, and 29.53in (750mm) free coil. Multiple coil models and sizes can adapt to work needs in various ways, making your workflow smoother. 3. LONG LIFESPAN: Each coil can resist overheating and premature wear, and they are durable enough to be used at least hundreds of times. 4. GREAT FLEXIBILITY: These induction coils are very flexible and can be bent for various purposes. You only need to bend them until you meet your expectations. 5. ADVANCED INSULATION: These coils are insulated to defend you and coated with wear resistant coatings. If the insulation layer is damaged, new coils need to be used. 6. EFFICIENT: Our induction coil kit is electroplated to avoid oxidation and ensure contact, providing maximum work efficiency. 7. WIDELY USED: Induction heater coils are mainly used to heat nuts and rusty screws to loosen them. Used for heat treatment of automobiles, machinery, and various small metal parts such as gears, pulleys, bearings, etc. Specification: Item Type: Induction Heater Coil Kit Product Material: Brass Brass Core: Approx. 2.5mm / 0.1in Product Specification: 4 piece set of 2.5mm brass core coil combination (1 for 20 30 40 type free type coils) Scope of Application: Used for dismantling rusty bolts and nuts Package List: 4 x Coil 1 x Storage Box How To Use Install and use!