I was figuring out what squat rack options there are, and came across volumes of discussions (mostly on bodybuilding.com) about power racks. It looks like a giant cage. My best guess is it is multi-level rack, but I am very confused about exactly what it does or if I need one. I want to squat and press without a spotter. So I'm guessing I don't need a power rack, but was wondering if anyone could tell me?