3100 SERIES PRESSURE/VACUUM VENT VTA 3" INLET SIZE, MATES WITH STANDARD ASME 150# FLANGED CONNECTION; RAISED FACE CARBON STEEL BODY, SST TRIM, CARBON STEEL WEATHERHOOD; FEP-TFE PALLET DIAPHRAGM; WEIGHT MATERIAL ALL SST; OPT-40: CONSTRUCTION PER NACE STANDARD MR0175;