Cooper T tank expansion chamber setup for remote line. What this does is you attach a tank to one side and a remote line to the other end and then on the other side you screw your tank in. And this acts as a giant expansion chamber for your co2. Gives a giant amount of volume before the air enters your remote line. Has some wear that is clearly visible in the gadget. The tank portion can spin. See photos for wear and how it comes apart. It slides back together.