Hollister Premier - Stoma Cap with Filter is a one-piece ostomy system. It does not require an additional ostomy wafer to work. The flat style of the SoftFlex stoma cap flange works with stomas up to 4" and the opening is 1 15/16". The adhesive is gentle on the skin. Stoma caps can be used for swimming, moments of intimacy, and in between ostomy irrigation sessions. Stoma caps are best worn when the stoma is not as active since they are not intended for volume. The integrated filter and odor barrier film allows the slow release of gas to help prevent gas build up or ballooning. This ostomy supply is available in a box of 30.