Adapter has a 0-4mm Chem-Vac™ Chem-Cap® valve between the top outer and lower inner joints, both of which are the same size. Available in two configurations: Style "A" having the valve mounted in-line, while Style "B" has the valve 90º to the joints with a brace permitting hanging of heavier objects from the line. Overall length of the 14/20 size is approx 135mm while the 24/40 is approx 190mm.