Emission Systems For Cars And Trucks Cheapest Parts On the Web

I was cleaning out my garage and I came across this part still sealed. It was for a 2003 Jeep Wrangler Rubicon but the jeep was wrecked in an accident (Not my fault- Some guy ran a red light. Luckily, a cop saw the whole thing. ). But I don't know what this part was for. Can someone please help me? I'm planning on selling the part on ebay but I can't explain it. It's from Mopar parts.
There are main two plugs?: One grey and One Black with a red release button.
One of the hoses have a white stopper-like end.
It looks to be about 3 ft. long.
I think it had something to do with the rear axle.