Image HT-Series ISO16028 Plug Product Options Part Number Length Maximum OD Body Size Thread Thread Size Material RD-HT4F4 2.63" (66.8 mm) 1.31" (33.3 mm) 1/2" Female NPTF 1/2"-14 Steel RD-HT4OF5 2.63" (66.8 mm) 1.31" (33.3 mm) 1/2" Female ORB 7/8"-14 Steel