The cords are securely and well. The L-plug fits perfectly into the headphone jack of my Notes in spite of the thick edge through the hardcase. Exactly what I was looking for.
In my opinion, the sound is not bad and no better than an expensive Aux cable, which has for example BOSE included here. (To use this cable, I had my phone always take from the hardcase, so the purchase of this cable.)
Strong buy recommendation for this price!