The Waterco O-Ring For Supamite / Supastream Pump Body is a replacement part for Waterco Supastream, Supamite, Aquamite, and Aquastream pumps. It is usually placed on the adapter plate. With no pressure, the natural resilience of the O-ring material will create a perfect seal and stop fluid or air from passing the barrier. When pressure is released, the properties of the O-ring material allow it to return to its original shape, maintaining the seal and the integrity of the O-ring.