MODEL "B2", BACK PRESSURE REGULATOR 1/2" SIZE, CV=0.30; 316L SST BODY, 316L SST SPRING CHAMBER; 302 SST W/TEFZEL RING DIAPHRAGM, TFE SEAT, 316L SST W/PCTFE SEAL, PORT CONFIGURATION "A"; FNPT END CONNECTION; 2-25 PSIG RANGE SPRING; NO INLET GAUGE; BLUE KNOB; VACUUM ASSIST SPRING;