The Waterco O-Ring Strainer Lid For Supastream & Supamite is a replacement part for Waterco Supamite and Supastream pumps. It is fit to replace the O-Ring Strainer Lids of both pumps. 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.