This product is a professional and practical check valve, made of safe and durable ABS material, with excellent texture, . It is a -way mainly suitable for aquariums and fish tanks, which can effectively protect your air pump in the event of a power failure. This is an excellent water tank accessory that will meet your needs very well. Features - Color: Mixed. - Material: ABS. - Size: About 5.50X1.00X1.00cm/2.16X0.39X0.39inch. - It is made of ABS material, which is safe, durable and good in texture. - The design is reasonable and the structure is simple, which can effectively help you protect the air pump. - Made with excellent craftsmanship, it has excellent durability and will not be easily damaged. - Professional and practical one-way valves can be well used in aquariums and fish tanks. - This is a very simple and practical fish tank safety accessory that will meet your needs very well. Package list: 18 x Aquarium Air Pump Check