A great way to set up a homemade Mash Tun. These fittings are designed to thread into the inside of a bulkhead fitting, and clamp down on a copper or stainless tube to allow for a hard-plumbed false bottom!  Simply thread the fitting into your bulkhead, loosen the nut, and slide your tubing in!  Tightening down the nut with tubing inside will clamp the internal locking mechanism onto your metal tube, creating a seal, and insuring a happy mash tun, happy beer, and happier drinkers!  ,304-Type Stainless Steel compression fitting.  1/2" Male Pipe Thread, with a 3/8" compression fitting on the other side.