Image In-Line Swivel Product Options Part Number Female Thread Size Male Thread Male Thread Size Female Thread Material D344R 1/4" NPT 1/4" NPT Brass D366R 3/8" NPT 3/8" NPT Brass SV17 1/2" NPT 3/8" NPT Steel SV20 1/2" NPT 1/2" NPT Steel SV26 3/4" NPT 3/4" NPT Steel