Features With Brass Core: Equipped with 2.5mm brass core, the induction heater coil can heat up to 1200℃ within a short time, improving your efficiency. 8 Pieces in All: There are 2pcs 20mm coil, 2pcs 30 mm coil, 2pcs 40mm coil and 2pcs flexible coil with 750mm length, which will meet your needs. Wide in Utility: Mainly used to heat up rusty bolts and nuts for removal, the induction coil can be widely applied on car, machine and so on. Better Crafting: Having been through electroplating, all the bolt remove coil are insulating, and very durable with oxidation in long using. Convenient Uses: Light in weight and compact in size as well, the induction heater coil can be neatly stored in box for convenient carrying. Specification: Item Type: Induction Heater Coil Product Material: Brass Brass Core: Approx. 2.5mm / 0.1in Application: Used for removing rusty bolts and nuts.  Package List:8 x Induction Heater Coil 1 x Storage Box Package List 8 x Induction Heater Coil 1 x Storage Box