Features: Efficient, effective for protection for your pump Great one way check for valve for aquarium air pump. Non Return anti siphon valves to protect your electrical equipment. (air pumps etc) for standard aquarium air pipe of 4mm inner diameter Small and compact,easy to install Specifications: Material: Plastic Length: app.4cm/1.57'' Main Color: Red Note: 1.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1 x One Way Check for Valve