Having lost my one and only BNC-to-N adapter, I had to find a replacement. The third local shop I visited (still) had them. A bit pricey, but readily available.
I had not handled too much the previous adapter (BNC-Female to N-Male), but these feel lighter. So I weighted them at 22 grams each. I have no means to evaluate their quality.
If weight is a synonim of quality, how much do your BNC-F to N-M adapters weight?
Note. These will be used for my RTLSDR receiver and in case of emergency when a proper coax is not available. If I will ever own a device with an N output, I will build a properly N-terminated coaxial cable.