The Culligan HD-950A Heavy-Duty Whole House filter housing 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. 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 HD-950A housing uses filter cartridges CW5-BBS, CW25-BBS, CP5-BBS, P25-BBS, R50-BBSA, and RFC-BBSA. Filter cartridge sold seperately.