The Tube/Stem Adapter is a two piece unit that is connected together loosely with a single bolt (3/16" Allen Key). The loose assembly is now placed into the stainless steel tubing until the crown of the Tube/Stem Adapter prevents it from going in any further. Now the Tube/Stem Adapter is tightened completely. The tightening process is pulling the lower piece of the adapter closer to the upper piece. As the lower piece is getting pulled up it is also getting pulled slightly sideways. This essentially turns the Tube/Stem Adapter into a wedge that is held firmly inside the stainless steel tube. The Tube/Stem Adapter is now solid and provides internal threads for the attachment of STEM SYSTEM components.