Product Information Material: Zinc Plated Steel Thread: SAE O-ring boss Select a Product Part NumberThread SizeWorking Pressure 1255-06H9/16"-185000 PSI 1255-12H1-1/16"-123500 PSI 1255-20H1-5/8"-122500 PSI 1255-24H1-7/8"-122000 PSI 1255-08H3/4"-164500 PSI 1255-32H2-1/2"-121500 PSI 1255-16H1-5/16"-123000 PSI 1255-04H7/16"-205000 PSI 1255-10H7/8"-143500 PSI