Large check valve for aquarium air pump Protect your air pump by preventing aquarium water from being sucked in in the event of a power outage. Small and compact / made of durable plastic Compatible with standard aquarium hoses with an inner diameter of 4 mm Colour: red Scope of delivery: 7 x valve anti-reverse < br/> Note: Since the above size is measured by hand, the size of the item you receive may be slightly different from the above. Meanwhile, please be reminded that due to lighting effects, monitor’s brightness/contrast settings etc, there could be some slight differences in the color tone of the pictures and the actual actual item. Your understanding is greatly appreciated. Package included