0.5m Toslink Cable - Toslink Optical Cable

I bought two of these. Ones of which does not stay connected, it slides out as soon as you take your hands off on both ends. I know it's not my TV or av receiver becauseI bought two of these cable. The 2nd cable just about works. One end fits well and stays put but the other end is very loosely fitted, any shake or tampering with other cables around it will make it disconnect.

I've owned TOSLINK cables previously which gave me the impression that the optical fibre could easily be damaged during tidying up etc, but this cable looks like it has a nice thick bit of armour sheath to protect the fibre from kinking or getting crushed. It links the PS4 to an external sound system and it sounds great! Also I have no sense of insecurity with the plugs that go into either port for connections, but once in place I am not repeatedly unplugging and replugging the cable.