Selecting the correct thread is important when choosing a replacement hydraulic quick-release coupling. When a device has a leaking quick coupling, we need to replace the quick coupling. It is important that we choose the correct thread for the hydraulic pipe or equipment, otherwise, the newly purchased quick coupling will not connect to the pipe. Usually, the threads used for connection are pipe threads. Only in rare cases, metric threads are possible. It is important to note that the inside diameter of the control thread is not equal to the thread size. This is a common mistake made by non-specialists.