The ostomy pouch and skin barrier, or wafer, are two separate and distinct components in a two-piece system. This provides the convenience of changing the pouch while the barrier continues to remain attached to the skin. The pouch is attached to the barrier either using an adhesive mount or snapped on by means of a flange which is a plastic ring on both the pouch and the skin barrier. The advantage of this system is that you can vary the size of the pouch you want to use, with a mini bag when involved in activities like swimming and a regular sized one otherwise. We carry a number of two-piece systems from top manufacturers like ConvaTec, Hollister, Coloplast, Cymed, Genairex and Marlen.