The OASE Magnetic glass cleaner 10mm takes the hassle out of cleaning your fish tank. For tanks up to 5mm thick, this OASE Magnetic glass cleaner 10mm effectively cleans algae and build-up from the inside out. Simply place one half on the inside of your tank and the other on the outside and start wiping. No more wet and cold hands with the OASE Magnetic glass cleaner 10mm!