Genuine replacement impeller for the Fluval CHI II Aquarium. Part number: A13979. Please check your manual to ensure you purchase the correct part. About Us: There are many reasons to shop online with Aquacadabra. Having traded online for so many years, we were one of the original specialist online aquatic retailers. As such, we have a huge wealth of experience in online trading. We continue to develop both our eBay shop and our operations to ensure we have the products you're looking for, at the right price, providing you with an enjoyable online shopping experience.