3100 SERIES PRESSURE/VACUUM VENT VTA 4" INLET SIZE, MATES WITH STANDARD ASME 150# FLANGED CONNECTION; FLAT FACE ALUMINUM BODY, ALUMINUM TRIM, SST WEATHERHOOD; FLUOROCARBON ELASTOMER (FKM) PALLET DIAPHRAGM; STANDARD WEIGHT MATERIAL STEEL OR COMBINATION OF STEEL AND SST;