I got my ebay catch can and obviously it diddn't come with instructions... but it includes the catch can, 1 tube, 3 clamps (weird number), and some piece that I have no idea what it is. This piece I'm talking about has an open tube at one end and then has a solid piece on the other... so the air just looks like it stops when it gets to it.

From what I understand about the catch can/pcv setup (which is a limited knowledge, mind you), you can go from the back of the stock box (back of the block) to the catch can, and then go to a pre-turbo intake or some other source of constant vacuum for best performance (or just go to atmosphere).

So, what the hell is this thing?

Open end:


Closed end:

 

I bought that same catchcan, I dont know wtf that thingy is either but I just ended up going to home depot and doing it hmt style with the air compressor filter. that one off ebay just doesnt look like its going to filter out the oil very well since theres no baffles or filter of any kind in it.