I bought a lot of these as I was making up a loom for the band as an experiment and wanted to use cheap plugs. Of the six cables I made up only two of them worked. I checked the cables were properly soldered and they were. On closer inspection it seems there is a very subtle difference in the shape of the valley in the tip of the jack plug. This means that it doesn't make a connection with some sockets. Here is the list:
Allen & Heath QU16, 6x all worked well YES
Electric fiddle NO
"Neutrik Rean NYS 2203 P" female sockets 2x NO
Plastic chassis mount mono jack socket YES
Acoustic guitar. YES
Some of these worked if they were pulled back slightly after insertion but in the end I had to change all of those ends for a different model plug. However I am continuing to use these on the other instruments and they are sill working well.
Maybe I was unlucky with having worn jack sockets although the Neutrik female sockets were new. Maybe it was a bad batch but that seems unlikely.
I don't like to give a bad review when everyone else's is so positive but for me these plugs were not really fit for purpose.