What is the small box under the passenger seat?

I'm replacing my carpet, and I just removed my passenger seat. What is underneath the seat? It looks like an amplifier-I'm not sure. I have all aftermarket stereo gear, so I plan on removing it if it is an amp. If not, what is it? Thanks.
 
Seems to me that there was an OEM amp under the pass seat in some cars. Someone can confirm that for you.
It's not a bad place to put an ignition box if you need a place to toss one.

Good luck.