<ul><li>1/4&quot; Industrial Interchange Series Type &quot;D&quot;.</li><li>Maximum working pressure 300 psi.</li><li>Plated steel couplers have hardened steel balls and stainless steel springs.</li><li>Heat treated to reduce wear on critical mating surfaces.</li><li>The industrial interchange series couplers interchange with Aro, Foster and Milton as well as units produced by other manufacturers. </li></ul>