An internally threaded, 2" diameter cylinder of hi-tensile, anodized aluminum; the inner threads are 3/4-14 NPS which will accept the standard, O-ring sealed scuba valve. A 3-foot (5,000 psi service) hose attached to the base of the stand has a scuba yoke on its free end for attachment to any tank. To test a valve, screw it into the cylinder, turn on the air, and submerge the cylinder / valve in water. Any leaks will be apparent, and all valve functions can be tested with or without an attached regulator. NOTE: Always hold the assembly securely and pressurize it slowly to prevent any hose whiplash. It can also be clamped into any vise.