This is a Metra brand wire harness that fits most Nissan 2007-Up Subaru 2008-2015 Harness
Sometimes in the Subaru the harness are tricky to know which is correct so the best thing is to remove the factory stereo and do a visual match up to see if this is correct.
 
This model number is 70-7552

You may use the fit guide at Metraonline.com to see which parts will fit your vehicle.

This harness is color coded and will help you install your new radio without having to cut off the factory harness. This is the right way to install a radio. You can solder this harness to your radio harness or you can choose to crimp it. 

Here are some tools and connectors that may help you install your own stereo:

https://www.franksaudiomotive.com/product-page/soldering-iron-kit-adjustable-temperature
https://www.franksaudiomotive.com/product-page/flush-cutters
https://www.franksaudiomotive.com/product-page/red-butt-connectors