4 X (10" X 2.5") 1 Micron ITM Polypropylene Sediment Replacement Filter Cartridges – SIZE: 10” X 2.5” 1.0 Micron Pack of Four (4) Use as a Stand alone Filter for Tank Water or ideally as a Pre-Carbon Filter in a Twin Filter Unit. Reduce your Water Filter Cost in a Twin Filter Sediment Carbon Filter Combination. Features: