Preserve and protect household plumbing and water-using appliances with the Culligan(TM) HF-360 Whole House Valve-in-Head Water Filter System. Installed on the 3/4-inch main water line at the point of entry, this filter housing is designed with a convenient built-in shut-off valve to stop the water flow at cartridge change time. The filter must be protected against freezing. The clear filter housing allows easy monitoring of cartridge life. For ease of cartridge change, a housing wrench is included. Because water quality varies, the HF-360 is sold without a filter cartridge. The following Culligan cartridges are compatible with this filter system; S1A, CW-MF, CW-F, P5 and P1.