This new Stainless Steel Sprouting Screen is convex, so it has improved drainage when the sprouting jar is inverted after each rinse. It fits any conventional 9cm (3½") Mason type sealing jar and allows for the free exchange of both water and oxygen to sprouting seeds. Add approximately one tablespoon of seeds to a clean sprouting jar and soak in clean, cold tap water for the desired time. Then drain and rinse, leaving the jar upside down in a bowl, so that it rests at about a 45° angle. This allows all the water to drain out between rinses. Be sure that the convex (dome-shaped) side is facing inward, toward the sprouts. This screen will not rust.