60-plate Brazed Plate Heat Exchanger, 1" MNPT ports Unit Dimensions: 4-1/4"x12" with 1" MNPT ports. Up to 600,000 BTU/hr 316L Stainless Steel - Copper Brazed (99.9% pure copper) - Flow Rate: up to 40 GPM Popular for domestic hot water heating applications Water-to-Water heating and cooling applications Outdoor wood furnace and wood boiler heating