Product features Inhibits scale and rust build-up Food grade crystals, with a 1 - 1.5 gpm initial flow rate The filter's crystals form a protective coating on all metal surfaces and safeguarding against corrosion Product description - The Pentek PCC106 water filter insert contains phosphate crystals that slowly dissolve in water to keep hardness minerals separated (up to 15 gpg) to prevent deposits. This is recommended for ice machines, beverage dispensers, food service equipment, water heaters and more. Product details - Shipping Weight: 1.4 ounces