JB Industries DV-29 Micron and Superheat Gauge Hookup Test Unit works with all micron gauges and creates a closed system eliminating leakage under deep vacuum and thus provides more accurate measurements. JB Industries DV-29 consists of a 10" metal hose with o-ring quick couplers, 90° male flare with 1/4in o-ring quick coupler, ball valve with o-ring quick coupler with depressor, and valve assembly with 1/4in male flare connections.