JB Industries DV-29 Vacuum and Hookup Test Unit creates a closed system to eliminate leakage under deep vacuum for more accurate measurements and can be paired with any existing vacuum gauge. The JB Industries DV-29 is comprised of a 10" metal hose with o-ring quick couplers, a 90° male flare with 1/4in o-ring quick coupler, a ball valve with o-ring quick coupler with depressor, and a valve assembly with 1/4in male flare connections.