Hoshizaki 4HC-H BW 4400 HF-H HC-H HF PRO 3500 HCH-CTO HFH BW 4400 BW7 TOS. Compatible Food Service Replacement Filter (3) Micron Rating: 0.5 Microns Capacity: 12 months or 12000 gallons 100% Made in the USA NSF/ANSI 42 class - Lead, Chlorine, Taste, Odor, Sediment, Particulate iron (i.e rust particles), Particulate lead and particulate class 1. NSF/ANSI 53 class - Lead, Mercury, VOC, MTBE, Cyst, Asbestos, and Turbidity. CARBON BLOCK WITH PHOSPHATE ( Scale Inhibitors ). KDF to inhibit the growth of bacteria.