Review on ISTA Connector 12Mm Control HOSEING by Eric Hay

This is exactly what I was looking for to adjust the high flow rate of my canister filter (Sunsun 303B). I had to slow things down as the flow was too fast. I keep both sides (inflow and outflow) in the same position (about 1/2 closed) to reduce the flow rate to a more consistent one. They are also handy for maintenance by closing the valves to disconnect my external filter. By the way, make sure you order the right size!