If you need a sub-out for 2.1, get the Fosi BT20A Pro (https://www.amazon.com/-/de/dp/B07JVFY27T/ref=sr_1_3?keywords=fosi+audio+bt20a+pro&qid=1682588449&sprefix=fosi%2Caps%2C150&sr=8-3) for a little more money. Mind that you need an ACTIVE sub and probably a Y-shape adapter cable.