Designed for whole house applications requiring 4.5 inch replacement filters, the Tier1 Replacement O-ring and Lubricant Kit For Whole House Systems works in most standard whole house water filtration systems. Replacing the O-ring helps to reduce risk of leakage in your housing as the food grade O-ring silicone lubricant preserves the integrity of your O-ring. Together the the O-ring and lubricant help ensure the system performs optimally. Order the Tier1 Replacement O-ring and Lubricant Kit For Whole House Systems today!