AKOAK 20 Pack Standard 4mm Inner Diameter Aquarium Air Line Tubing Fish Tank Oxygen Air Pump Volume Flow Control Valve（Grey）

DO NOT WASTE YOUR TIME WITH THESE!!!I grabbed a 20 pack of air valves from this company and more than half of them came defected with extra plastic attached to the top of the knob when the caps are off. This led to the caps of the knobs cracking and breaking, which made them completely useless. Save yourself some time and go with the Asamuyu brand which is also sold on amazon. They give you a 30 pack instead of 20 for around the same price and with MUCH BETTER quality. None of the air valves came with that extra plastic that messed up these ones. This company needs to really check the quality of their valves before sending out more. Would hate for more people to get cheated like I did.

Works good. Just as described. Fast shipping!

As advertised

They work just fine but I wish there was a mix of valves instead of all the same.

I've ordered 2 packs of these. It seems approximate 4 out of each bunch dont work. I guess it's still a good deal though.