This Gen2 NFC patent has obtained the protection of many national invention patents in the world, including the approval of the European Union. This innovative invention solves the common blood return condition in medical clinics. If the needle-free connector mechanism does not protect the cavity, the blood will cause thrombosis when the blood is returned to the needle-free connector cavity. The medical staff has to spend time and cost to inject the anticoagulant. When the needle is pulled, the conduction tube is retracted and closed. This neutral design, because the bottom is closed, when the patient raises the arm and causes blood to return, it does not return to the cavity. If In the cavity will triggering a thrombus, so our Gen2 needle-free connector greatly reducing the risk of secondary infection. Our needle-free connector technology and patents specifically address this situation for medical staff and patients. When the needle is closed, the catheter is closed first, then the surface is sealed, the flat design is easy to disinfect, the catheter design is cylindrical and there is no corner, and the world's minimum residue The amount of 0.016ml will not cause many problems of flushing and waste of liquid medicine.