Both have the same pitch diameter at the top of the hole of internal threads or end of the pipe on external threads, and both have the same thread lengths or depths.
在内螺纹的孔的顶端或者外螺纹的管的端部拥有相同的中径，而且拥有相同的螺纹长度和深度。
2
The open topend has a predetermined diameter, the receptacle being adapted to be flexible and resilient.