Which wiring harness can I utilize to connect to the MP5+ Stereo ? Aquatic AV July 16, 2020 19:59 Updated The harness used for this particular stereo is the AQ-UNH-2. Related articles MP5+ Stereo (MP521) - Owners Manual Can I install the marine model stereo into my Harley Davidson motorcycle ? Is the MP5+ Stereo an upgrade from the AQ-IP-3B ? What comes inside of the box? How big is the storage behind the faceplate? Can I fit my phone in there? Comments 0 comments Article is closed for comments.