My Apeks TX50 primary with a Zeagle 90° Swivel Elbow on a 40" 3/8" hose, routed under the right arm for your garden variety singletank openwater diving.
All regulator hoses have a built-in pivot that normally allows the second stage to pivot vertically (mouthpiece up/down). In this case the hose attaches to the bottom of the elbow, so the hose pivot is "around" (left/right).
The elbow then has its own built-in pivot at the knurled section (with a std 9/16" wrench fitting) between the elbow and the regulator. This provides the same vertical pivot (up/down) you expect on any "normal" regulator via the normal regulator hose.
