Part fell out. ID?

[jfcasey]

I finally got around to taking a picture of this. Right after I bought my truck, I brought it in for an oil change, threw it up on the lift, and found this thing sitting in the arm pit of where the lower control arm meets the sub frame. Anyone who has torn these trucks apart recognize it?

I found it 6 months ago and haven't had a problem, so it cant be that important but I'm curious as to wtf it actually is. My guess is part of some valve, but no idea what valve.

 

[Earl43P]

Some mechanic is wondering where that part of his pneumatic hammer/air chisel went when it kablooie.

 

[Viper Command]

Some mechanic is wondering where that part of his pneumatic hammer/air chisel went when it kablooie.

It does look like its to an air tool.