In the Dansac Duo Soft two piece system you can mix and match wafers (skin barriers) and pouches/stoma caps, but you have to use items with the same “Ring Size”! If your stoma is less than 1 1/8” (28 mm) you would probably use the wafer with the smallest ‘ring size’, which is 1 7/17” (=36 mm, Ring Size 36): Wafers 436-xx, 536-xx of 736-xx. The –xx indicates, for pre-cut wafers, the pre-cut stoma opening (in mm) of the wafer, e.g. 536-20 is pre-cut 20 mm. All cut-to-fit wafers end in -15, which in this case indicate the size of the starter hole (15 mm). Wafers starting with 4 (e.g. 436-15, cut-to-fit, Ring 36) have an ‘extended wear’ barrier, wafers starting with 5 (e.g. 555-35, pre-cut 35 mm, Ring 55) are ‘regular’ wafers and wafers starting with 7 (e.g. 743-25, pre-cut 25 mm, Ring 43) are wafers with convexity. When selecting a pouch/mini cap/irrigation sleeve, the ‘model #’ is followed by the Ring Size (e.g. 501-36 is an opaque, closed end pouch, Ring 36 while 512-43 is a clear, drainable pouch, Ring 43, etc).