Penn-Plax Tank Dividers instantly convert one aquarium into two! Quick and easy to install, these polymer screen dividers are great for creating breeding tanks or for separating rough fish. The perforated screen allows unrestricted circulation filtration and even heat flow. Available in four different sizes to fit most tanks up to 55 gallons in size, these dividers can be trimmed to fit your tank perfectly. A convenient and efficient way to protect your fish without major modifications to your tank. From the manufacturer: Penn-Plax is a family-owned business that was established in 1956 in Brooklyn, New York. Over the years our goal remains the same: to enhance the pet ownership experience. We specialize in creating excellent pet supplies for animals, both great and small. We're best known for producing pet products at affordable prices. Our brand, Penn-Plax, is synonymous with innovation and quality, keeping your pet foremost in mind.