Pentek WS-10 Water Softener 10&rdquo;Cartridge, 155319-43 Reduces hardness minerals and scale deposits in low flow rate residential and commercial applications Cation, sodium-form resin ion-exchange media with polypropylene pre- and post-filters Capacity of 750 grains Recommended flow rate of 0.50 gpm Maximum temperature of 100 degrees F (37.8 degrees C)