If you’re looking for sturdy, easy-to-attach aquarium valves for your RO/DI and other water applications, then you ought to have these Hayward valves. They are the industry standard when it comes to PVC valves so it’s the brand of choice if you’re looking for maximum durability. Hayward Double True Union Ball Valves have threaded and slip adapters and is made from the highest quality PVC material. These valves eliminate the need for unions and makes it easy to remove a piping system because there’s no need to alter connections. Hayward True Union Valves come in 1”, 1.5”, 2”, and 3/4” sizes.