Review on 🐠 BornFeel Plastic One Way Non-Return Check Valves 16pcs - Aquarium Air Pump Accessories for Fish Tank by Katrina Brown

No complaints yet. They work great. I will keep testing and playing with them. If something slows down or doesn't work I will update my review! :) I would definitely buy it again! Update: I ran various tests on them and found that ONLY ONE of them didn't work perfectly. If I blow slightly the wrong way it still lets some air through, but if I apply a little more pressure it closes immediately. So this is still the trick for my app. I said I would update if any problems were found. :) After all the tests, I'm still happy with the purchase.