Check the listing for details. EHEIM 2506751 EHEIM FIX 5 litre Mechanical Filter Media Aquarium. Condition: New, Made in Germany. Listed at 31.28 USD. Prefilter material and fine filtration – as a separation layer between the mechanical and biological filter media This specially formed filter material is for use after the layer of Eheim MECH or MECHpro. Eheim FIX acts as a separation layer between the mechanical and biological filter media. This is where the larger dirt particles are trapped, thus removing them from the water before entry into the biologically functioning filter layers.. We aim to dispatch all items, purchased and cleared payment received by 1.00pm, on day of purchase - ensuring lightning fast delivery. Please bear in mind it is dispatch time and not delivery time you are marking us on. We do our best to offer you a 5 star service if you feel for any reason you have not received this, then please contact us prior to l.