Help needed in Radiator Replacement

I'm replacing a leaky radiator. I've purchased an after-market rad, which supposedly matches my cars make/model, and looks like a single fin bed unit. However, my existing cooling system seems to have two fin beds, i.e. two radiators, one behind the other, where only the front one has the radiator cap, etc. Am I to replace both, or just the front one? Why does it seem I have two radiators?

The smaller one is probably your AC Condenser, it will have smaller metal pipes running to your AC Compressor.

Thanks, I'll check it out. If my air conditioner doesn't currently work, should I think about doing any work to this AC Condenser as well, while I'm doing the rad?

The smaller one is probably your AC Condenser, it will have smaller metal pipes running to your AC Compressor.