Features: Multiple connectors can achieve various M2 (shared by M2.5), M3, M4, M5-, M6 (1/4") , -M8 embedding of hot melt nuts. Compatibility with standard 936 universal soldering iron head, convenient and practical. The design of son-mother head, with hand-twisted knurled joints, allows for the removal of the head joint at any minutes now in a cooling state, different types of thread indenters can be replaced. Brass material, with good thermal conductivity and end face contact, prevents nuts from tilting and facilitates quick insertion of nuts to plastic part. After the pressure head is pressed in, a small distance is inserted to avoid the plastic part, making it difficult for the head to damage the plastic part, and it can be inserted into the interior of plastic part to a certain depth. Specifications: Material: Brass Type: 1 Set Packing Size: Approx. 3.5x3.5x2cm/1.37x1.37x0.78inch(plastic box packaging) Scope of Application:Interchangeable to standard 936 universal soldering iron head for M2 (M2.5 shared), M3, M4, M5-, M6 (1/4 "), M8- and other hot melt nuts or embedded part, commonly used for 3D printers printing hot melt-copper nuts or implanting nuts on plastic Package Includes: 1x Connector 6x Indenters note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.