Koller Products Filter Cartridge Pre-Assembled fits Tom Mini Power Filter (TM1250), 3-Pack Dense foam insert with premium activated carbon, all-the-while keeping aquarium water crystal clear. Maintains optimal water parameters, keeping water crystal-clear and fish healthy Quickly removes fish waste and water discoloration. 100% Customer Satisfaction Guarantee. If we can be of any service please contact us at customercare@kollerproducts.com, we want to keep you happy.