3.5" stereo splitter . Splits sound to two headphones without any sound issues.
I brought this to share music & movies with my wife while enduring an 8 hr plane ride. The unit was plugged into my samsung s7e and the other leads went to our head phones. Everything worked perfectly, but I removed one star only because the plug that sticks in my phone was so big that it couldn't make a proper connection without removing the phones case. It was an inconvenience for me to make it work properly.