Made by Waterway USA
This non return valve is designed to fit into rigid 1.5" plumbing to stop water for going down the plumbing into the air blower.
It has a spring inside with a cone and seal and when the air switches of this returns to a closed position. Arrows on the side show the direction of flow.
The part is found on nearly all American and UK manufactured hot tubs and spas and is easily fitted / replaced with some UPVC glue.
Please note for best results we advice to also take the plumbing upto the highest level inside the hot tub and have the valve fitted in the vertical position.
If you do need help with part however please get in touch.