You will notice on most all black iron pipe threads, there is a taper near the end of the threads. It is at this taper that the pipe and fitting tighten up, making for a tight seal. On these particular fittings, two of the four threaded holes seem to be tapped completely through without the taper. As such, the pipe you will be inserting into said holes will not be tight, but sloppy. If I wasnt in a rush for this job, I would return. I had to build up the thread diameter of the pipe with tape to See full review