The thread is NPT 1/2, Please check the Thread. We have received some refund customers that marked the thread wrong thing, actually they don't understand the NPT Thread is the pipe thread standard in North America, and it is not equal to 1/2" of the inner diameters you measure it directly. Please check the thread carefully. <b>As customers requirements, we update the coating from Zn to Zn-Ni alloy, this coating would be better performance and we keep the same price.</b><p>AKJia couplings are manufactured to the new ISO 16028 standard which guarantees:</p> <ul> <li>Interchangeability with other couplings made to ISO 16028 standard</li> <li>Dependable quick coupling operation that can be used in high operating pressures and high flow rates.</li> <li>Long lasting performance</li> </ul> <p>Interchangeable with:</p> <p>Parker FE Series</p> <ul> <li>Male: FEM-502-8FP</li> <li>Female: FEM-501-8FP</li> </ul> <p>Safeway FFE49 Series </p> <ul> <li>Male: FFE491-4</li> <li>Female: FFE495-4</li> </ul> <p>Faster FFH Series </p> <ul> <li>Male: FFH08 12NPT M</li> <li>Female: FFH08 12NPT F</li> </ul> <p>Eaton Aeroquip FD89 Series </p> <ul> <li>Male: FD89-1002-08-08</li> <li>Female: FD89-1001-08-08</li> </ul> <p>Snap Tite 74 Series </p> <ul> <li>Male: 74N8-8F</li> <li>Female: 74C8-8F</li> </ul> <p>Stucchi FIRG Series </p> <ul> <li>Male: 800801007</li> <li>Female: 800801006</li> </ul> <p>Dixon HT Series </p> <ul> <li>Male: HT4F4</li> <li>Female: 4HTF4</li> </ul> <p>DNP PLT4 Series </p> <ul> <li>Male: FF-HPG-08-08N-NPT</li> <li>Female: FF-HPG-08-08C-NPT</li> </ul> <p>Tomco FE Series </p> <ul> <li>Male: EP4-26</li> <li>Female: EC4-26</li> </ul>