Check the listing for details. "O" rings for Hydor External Canister Filter Prime 20 for Aquariums. Condition: New. Listed at 8.00 USD. Upgrade the performance of your aquarium with these "O" rings designed for the Hydor External Canister Filter Prime 20. Suitable for all water types and tanks with a capacity of 30-60 gallons, these rings ensure effective filtration without compromising the flow rate. They are easy to install, durable and highly reliable, providing a long-lasting solution for maintaining a healthy aquatic environment. Whether you're a seasoned aquarist or a beginner, these "O" rings are an essential part of your aquarium maintenance kit. They are a perfect fit for the Hydor External Canister Filter Prime 20 and guarantee a hassle-free experience. These rings are a must-have for any aquarium enthusiast looking to optimize their filtration system and keep their aquatic pets healthy and happy.