Review on 🐠 Asayu Aquarium Air Flow Control Valve Splitter Set - 5 Pcs (1-Way, 2-Way, 3-Way, 4-Way, 5-Way) with 6pcs Suction Cup - Pump Accessories by Beny Teller

They are great for aligning bubblers and routing hoses. the diameter of the inputs/outputs is slightly larger than that of T-connectors. I coated them all with silicone oil so I could easily turn the tubes on and off. Each inlet and outlet can be adjusted from 0 to full flow and to just the right position. It's possible to turn off one bubbler at a time to clean while other bubblers aren't a great way to install them, so I used a zip tie. I currently only use the 5th way, but have also tested the 4th way. They appear to be durable and I expect them to last for years.