Product review (4 stars): Cartriges are good but frustrating to change
I've used these cartridges for several years for the Omnifilter whole house water filter that a plumber installed but it isn't easy to replace the filters because they don't stand up straight in the bowl while you're trying to screw the vertical bowl back into place. It's not the cartridge's fault but rather the design of the filter system. I wish there were a way to get the cartridges to stay in place rather than to fall to one side or the other while you're screwing in the bowl back into place. Amazon's prices are still the best I've found anywhere.