Metric thread type is most common in Europe. The male has a 24° sealing angle cone seat with straight metric threads.The female has a 24° convex cone with O-ring and a swivel straight metric threaded nut.It has a cylindrical inner and outer diameter precise in millimeters. The fine taper of metric tapered thread allows for the best possible force transmission. In writing, you can identify metric threads by a capital “M” plus an indication of their nominal outside diameter (ex. M22 x 1.5). Lastly, when measuring pitch size make sure you’re using a metric pitch gauge.