1No damage to the glass, easy for cleaning, wear resistant and durable algal removing knife. 2Anti-scratch sticker, when moving the downy brush, hook on the inner brush catch the garbage and algae stuck to the cylinder body. 3Magnetic brush and scraper can used replaceable, one brush for two uses. 4Suspension design to prevent the magnetic brush from sinking to the bottom of the cylinder. 5Non-slip handle design, easy to operate and convenient to use.