OMNIFilter's U25 10" whole house valve-in-head water filter system is designed for average size homes with 3/4" incoming water lines and is ideal for both well water and city water applications. The valve-in-head feature turns off the incoming water supply for changing your cartridges. The clear housing allows you see your filter working and gives you an indication as to when to change your cartridge. The system easily attaches to any 3/4" incoming water line to filter water for the whole house. Supplied with a 5 micron TO1 sediment/taste and odor cartridge to handle water with sediment, tastes and odors, however you can customize it to your filtration requirements by using any number of OMNIFilter cartridges. IMPORTANT LEAK PREVENTION STEPS: The rubber o-ring provides the water-tight seal between the cap and the bottom of the housing. It is important that the o-ring be properly seated in the groove above the threads of the housing. Lubricate o-ring with clean silicone, insert o-ring into groove, and smooth into place with finger. Screw bottom of housing onto cap and hand-tighten. DO NOT OVER-TIGHTEN.