EHEIM MECH (formerly Ehfimech) are hollow ceramic cylinders for effective mechanical filtration. Directly after the entry into the filtration cycle, the water is swirled through the hollow ceramic material. Through this action, the coarse dirt particles sink to the bottom. The pre-filtered water treated in this way continues ist route through the other filter layers. EHEIM MECH can be washed under lukewarm water and can be used several times. To be used in fresh and marine water.Do you have questions about this article ?