I used this for about a year it worked great. You need this harness if you put an aftermarket radio in your outlook, acadia, enclave, traverse or any other gm vehicle with onstar without a factory amp. I also wired it so you can watch a dvd while driving (relay switched to ground). I can go 85 shipped paypal. This is plug and play for all aftermarket stereos. I also have the speaker brackets to install 6.5" speakers in the doors and installation plate that fits around the radio. This is all necessary to replace the horrible crappy factory speakers and radio in your vehicle. There was a huge difference.