Please carefully choose the option based on your Model 3 built year.
With this speakers activation set / wire harness, you can activate the 6 (only 4 in post-March 2020 models) inactive speakers on your SR+ Model 3.
The work is done by connecting the front dash speakers parallel with the tweeter and A-pillar speakers to feed the signal for the speakers, and connecting the rear door speakers in parallel with the rear shelf speakers.
If your Model 3 is built post-March 2020, you can choose the option to add the 2 rear shelf OEM speakers.
If your Model 3 is built post-October 2020, you will need to tap 2 wires to enable the front right tweeter (the plug-and-play connector is removed).