Because my AV receiver outputs no sound via HDMI, I needed mandatory optical digital cable for audio transmission. Already another (and 10 times as expensive) hanging between BluRay player and amplifier. For trial and error I have now still plugged this second Billigheimer part between TV and amplifier. Works just as well as the expensive cables. I'm thrilled! From puny diameter should not be deterred. This is what counts not at all in light guides. The decisive factors are processing the conversion to contact head and enough boot. Both are given in this cable. However, I had some problems during the engagement of the contacts; it brauhcte a lot of pressure, until it has made audible click. That was much softer in my other cables. But is also the only shortcoming. Can only recommend at this price the cable.