PRACTICAL CHANGE SYSTEM: Due to the thread in the soldering iron adapter, the soldering tips can be changed very easily WITHOUT completely unscrewing the soldering iron. 3D PRINTER PARTS: 3D printer soldering tips are commonly used for 3D printers to print parts with hot melt copper nuts or to implant nuts on plastic. EASY TO USE: The small distance embedded in the pressed avoids the plastic parts, so the is not easily damaged to the plastic parts, and can be inserted into the plastic parts to a certain depth. 936 UNIVERSAL SOLDERING IRON TIPS: Soldering tips are interchangeable with standard 936 soldering iron tips for use with M2 (M2.5 common), M3, , M5, M6 (1/4 inch), M8 and other hot melt nuts or inserts. BRASS MATERIAL: Heat set inserts are made of brass for better thermal conductivity and face to face contact to prevent nut skewing and facilitate quick insertion of nuts into plastic parts. Material: Brass Color Package Contents: 1 x Embedding Tool kit