Features: Pretty insulation: The ceramic coil is insulative, which can be exposed to water, kerosene and metal (except the wire connector), you can rest assured to use safely. Extensive usage: The ceramic coils are with small size and simple operation, ideal for students majored in electronics, to lean about electric circuit and develop their handmade ability. Specifications: Materials: alumina ceramics, aluminum Size: Head diameter: 0.43 inches/ 11 mm Head thickness: 0.05 inches/ 1.25 mm Maximum voltage: 4.2 V Power: 36 W Power resistance: 0.45 - 0.65 Tensile force: 3 kg Package includes: 4 x Ceramic coils Note: When heating in air, the surface temperature should be less than 400 degrees, and protect from splashing liquid to avoid destroying the porcelain body. When heating the parts, it should be closely attached to the parts. If not attached tightly, it will heat unevenly, and the temperature difference of the body will destroy the heating element. Please keep away from little kids to avoid poking risk.