Color: Silver. Material: High-grade Oxygen-free Copper. Size: as shown. Plated with Lead-free Solder. Replacement Iron Tip for 936 937 Series Soldering Stations. Features: If you do not use an iron, do not let the iron run for several hours. This allows the tip to get a black oxide layer. Try tinning the tip while heating. If you leave it for too long or run it too hot, it will burn off the solder and turn black again. These soldering iron tips are suitable for 936 937 soldering stations. Package Included: 1 x Solder Iron Tip