Review on Anderson Metals Forged Fitting Degree by David Romo

National Pipe Thread Taper (NPT) is the US standard for tapered threads used on pipe and fittings with thread are used. National Pipe Thread (NPT) threads are slightly tapered, meaning the threads get larger as you screw them in. This ensures an airtight fit. It tightens as you twist it. These threads are straight. I installed this in my workshop air compressor lines and can only fit 3 threads to any other NTP fitting. I've even tried a few other connectors that I know are 3/8 NTP. That tells me they don't taper and once the threads hit the cone they don't go any further. I could use that, but I don't feel comfortable using only 3 threads on a 175psi system. It looks high quality, but if I can't refill it, it's useless.