Cymed Seals - Flexible Washer Ostomy Rings/Seals are moldable, stretchable washers that can be shaped to fit any size stoma. Provides a waterproof stoma seal that protects the skin. This skin barrier is also used to fill in irregularities around the stoma. Cymed provides unmatched confidence and security in ostomy seal supplies. Size: 2 3/8" outer diameter with 3/8" doughnut hole.