The iDatalink ACC-HU-PIO1 adapter allows you to connect select Pioneer radios to compatible iDatalink T-harnesses. This extra harness takes the place of the harness that comes with your new Pioneer stereo. It connects directly between select Pioneer radios and the latest Maestro "Head-unit ready" T-harnesses so you won't have to splice any wires.Note: This harness will not work by itself. You Must Also Have an Idatalink Maestro Interface Module (ADS-MRR or ADS-MRR2) and a Compatible Vehicle-Specific Idatalink Maestro "HRN-HRR" T-Harness. (It MUST be the HRN-HRR version, NOT the HRN-RR one.) Sold separately.