Constructed of 316L stainless steel, this shell & tube heat exchanger is a very reliable and effective way to transfer heat indirectly between the outdoor furnace and pool or spa circuit. Unit is designed for either horizontal or vertical mounting (mounting brackets are included). The unit should always be mounted to a wall, ceiling or floor to prevent vibrations or water hammer which could damage the unit. Used in same applications that MPN plate exchangers are used. Not recommended for use with salt chlorinated pools or hot tubs.