Sorry, I can't believe nobody told you yet, sorry. You need this tool it's shaped like the letter "U". There's a set of two and they'll fit in those holes on the sides of the stereo. When you insert them you'll hear a click and it will pull right out. Go to the local stereo shop and buy a wiring harness and 1/4" trim ring (they'll know what you're talking about). It'll make the install much easier.