EHEIM Mech Mechanical Pre-Filtering Medium (Hollow Ceramic Rings) 5L;

Shaped as smooth, hollow ceramic tubes, this mechanical filter media works much like a sieve trapping particulate waste as it passes through the material.EHFIMECH (Hollow Ceramic Rings) 5L: A coarse mechanical filter material which is to be used as bottom layer filtering. Its hollow ceramic design creates eddies which disburse the water into many paths. It traps large debris while creating an even flow of water for subsequent layers.