Single pass type. Rated for 150 PSI @ 350°F. MFR # E375-0952. National Board # 35189. Unit has a 10"Ø carbon steel shell with an 84" tube length. The 3/4" O.D. X 18Ga tubes are constructed of 316 stainless steel. 76 tubes make up the bundle. Pfaudler Sybron Corp of Rochester, NY