I have been using a lot of NPT brass fittings recently. After some experimentation, I have settled on using Anderson fittings whenever possible. I purchased several of these in three different sizes and all functioned perfectly. That is not to say that the finish was perfect (it was not..) or that the casting was perfectly centered (it was not..). However, the fitting threads were well machined and were well within specification for NPT. I have had many fittings over the past year that failed miserably because the threads were not cut to specification. Some were difficult to start, others were undersized to the point they would not tighten leak-free. These Anderson fittings do not have those problems.