Boyu Magnetic Cleaner With Thermometer [WD-Series] Magnetic Scraper Boyu WD-Series is designed to clean the glass (up to 12 mm) of the aquarium without damaging the glass. Equipped with a digital thermometer to determine the temperature anywhere in the aquarium.  When separated from the outer part, the submersible part floats to make it easier to remove from the aquarium. Sizes: S : 10.4x4.3x6.2cm M : 11.4x4.7x6.8cm L :  12.85x5.3x7.4cm