4) New Unicel C-5625 Spa Replacement Cartridge Filters 25 Sq Ft Jacuzzi CFR-25 Industry's most complete line of replacement filter elements Emerald Spas (Note: This product has no center core.) Jacuzzi Brothers (42 2891 08 R) (Note: Jacuzzi part number formerly 42 2763 03. This product has no center core.) Jacuzzi Whirlpool Bath (5475000) (Note: This product has no center core.)