Useful 1Pcs One Way Non-Return Check Valve Aquarium Air Pump Accessories Compatible with 4mm Air Pipe Black Function 

Features:
Safe and durable products, great one way check valve for aquarium air pump
Protect your air pump by preventing aquarium water from back siphoning during a power outage
Place in your airline tubing between your air pump and aquarium water to prevent water returning down the air line.
Made of durable plastic,small and compact,It's easy to install
Compatible with standard aquarium air pipe of 4mm inner diameter
Perfect accessories for better life

Specifications:
Material: Glass
Dimension: Approx.105mm x 12mm x4mm (Length*Diameter*Tubule diameter)
Color: transparent
Quantity: 1pcs

Including:
1pcs Transparent Aquarium Check Valve