4 X (10" X 2.5") 20 Micron ITM Polypropylene Sediment Replacement Filter Cartridges – SIZE: 10” X 2.5” 20 Micron Pack of Four (4) Use as a Stand alone Filter for Tank Water or ideally as a Pre-Filter before the Carbon Filter in a Twin Filter Unit. Reduce your Water Filter Cost in a Twin Filter Sediment Carbon Filter Combination using the Sediment Filter to reduce Sediment load on the Carbon Filter.. Features: