The Culligan(TM) HD-950A Heavy-Duty Sediment Filter allows you to preserve and protect your household plumbing and water-using appliances. Designed for installations where a 1-inch water main is present at the point of entry, this filter housing features a pressure relief button used at cartridge change time. The filter must be protected against freezing. For ease of cartridge change, a housing wrench is included. The large filter size provides extra capacity where high sediment concentration is an issue. Because water quality varies among locations, the HD-950A is sold without a filter cartridge. The unit comes with a 5-year limited warranty. The HD-950A housing uses filter cartridges R50-BBSA, CP5-BBS, and RFC-BBSA.