1pc vs 2pc Ostomy Appliance – OSTOMY TIPS (w/ video)


Ostomates have a lot of options to choose from when it comes to pouching systems, but it’s not always clear what the advantages and disadvantages are between a one-piece or a two-piece system. I hope that you’ll be able to learn the differences in the following post.


One-Piece Ostomy Systems

one-piece ostomy pouches
One-piece ostomy pouches from Coloplast, Perfect Choice and Nu-Hope

This is probably the ostomy system you’ll leave the hospital with. A one-piece means that the wafer (the part that sticks to your skin) is fused to your pouch right of the box. You can’t separate the pouch from the wafer.

Advantages of a one-piece appliance

  • Lower profile vs most two-piece systems.
  • Usually costs less than two-piece systems.
  • Less supplies to manage.
  • Some people find them more comfortable, especially if they have a less-than-perfect tummy or a hernia.
  • Zero chance of your bag falling off (but the wafer still can!).
  • Takes up less storage space, especially in a travel bag.
  • Less time to make an appliance change.

With a one-piece, the goal is simplicity. Some people love the minimal aspect of a one-piece, but there are some disadvantages too, assuming they are things that you find lacking.

Disadvantages of a one-piece appliance

  • Higher chance of getting an imperfect fit.
  • No option to rotate your pouch at will (an advantage if you use a Stealth Belt).
  • Can be more difficult to apply.
  • If you have to change the wafer early, you end up having to throw away the pouch, too.
  • If you have a problem with the pouch portion, you have to change the wafer, too.
  • No option to change to a different size/style pouch to accommodate different activities.
  • Can’t use pouch liners.
  • Can’t easily “burp” your pouch to get rid of excess gas.
  • Changing closed, one-piece pouches often can lead to skin irritation.

So while you have simplicity, you also lack some flexibility in options. In my experience, one-piece appliances are comfortable, but I always feel that I’m not getting a perfect fit around my stoma in the same way that I can with a two-piece, especially with seeing and/or correcting a gap that might be between my stoma and the cut-out in the wafer.

Two-Piece Ostomy Systems

With a two-piece, you have a separate wafer and pouch. You have an option of sticking the wafer to your skin before applying a pouch, which means that you can have a better look at your stoma and that usually results in achieving a better fit. There are several types of two-piece systems, and each manufacturer has their own coupling method. Here are the most common types:

Adhesive coupling

two piece adhesive coupling ostomy pouches
Two-piece ostomy pouches with adhesive couplings from Salts and Cymed

Like a hybrid of the two different ostomy systems, an adhesive coupling offers you some advantages of having a two-piece, but with the low profile and the added comfort of a one piece. This is done by replacing a hard plastic coupling with an adhesive coupling, which you stick onto a designated spot on your wafer. While some manufacturers say that you can remove the pouch and reapply/adjust it, many ostomates find that doing that is just asking for a leak.

Leaks are a big disadvantage with adhesive coupling systems. If you don’t stick the pouch perfectly onto the wafer, you’ll get a leak between your pouch and wafer. For that reason, I don’t suggest this type of coupling system to anyone who has dexterity, mobility or vision problems.

Some ostomates will stick the pouch to the wafer before applying the wafer to their skin. This effectively means that you are using it as a one-piece.

Mechanical coupling (with lock)

two piece ostomy pouch with locking coupling coloplast
Two-piece ostomy system with locking mechanical coupling. Coloplast Sensura Mio 2pc

This is an option that Coloplast has perfected, and it’s a huge part of the Click line of products they offer. This system allows you to mechanically snap your pouch to your wafer and then lock it in place. The beauty of this coupling is that it allows you to lock and unlock your pouch whenever you like, which is handy for rotating your pouch at will (like when using a Stealth Belt).

I feel completely secure when using a locking coupling, and if you have a high-output stoma which has resulted in your pouch falling off in the past, then this is a system you might want to try. If you have dexterity or mobility problems in your hands, especially joint pains, then you might find the locking mechanism to be difficult to use. I’ve read stories on forums where this has been an issue.

Another advantage that I’ve noticed when using 2pc systems with mechanical couplings is that it offers some basic level of protection against impact since the coupling is raised a bit. If your stoma is flush or slightly protruded, then this might be a good alternative to stoma guards (again, for very basic protection).

Mechanical coupling (snap-in)

two piece ostomy pouches mechanical coupling
Two-piece ostomy systems. Mechanical snap-in style from Hollister on left. Locking couplings from Coloplast on center and right

This type of two-piece has a simple system that allows your pouch to snap into place on the wafer. This is common on Hollister products and works well. There is a small chance of your pouch falling off or leaking if it’s full and you’re doing a lot of running or jumping, but using a support belt or ostomy wrap will add an additional level of security to help prevent those issues.

One thing that I’ve found with snap-in couplings is that you can’t easily rotate them. You have to take your pouch off, rotate, then snap it back into place. While that sounds easy enough, I find that it only creates an opportunity for leaks.

I’ve found an easy way to help rotate these stubborn 2pc systems. Check it out HERE.

As I mentioned in the section above, this style of mechanical coupling may also give a basic level of stoma protection.

Advantages of a two-piece appliance

  • Allows for rotation of the pouch (some two-pieces).
  • Some mechanical coupling 2pc systems are easy to “burp” when gas builds up.
  • Can make it easier to get a perfect fit around your stoma (allows visual confirmation that the wafer was cut properly).
  • Allows you to replace your pouch without having to change your wafer.
  • In the case of an ileoscopy (scoped through the stoma), you likely won’t need to remove your wafer and can simply remove your pouch.
  • Allows you to swap between different pouches (that are compatible with your wafer); great if you use a high-capacity pouch at night and a smaller one during the day.
  • Can be used with disposable pouch liners.
  • Two-piece systems with mechanical couplings may offer some level of protection against stoma impact.
  • If you’re a colostomate and you irrigate your colon, using a two-piece system allows you easily remove your primary bag and swap it with an irrigation sleeve, then replace it when you’re done – all without having to remove your wafer.

Disadvantages of a two-piece appliance

  • mechanical couplings add stiffness and bulk to the pouch; locking couplings are even more obtrusive
  • more expensive to purchase a separate wafer and pouch vs. a one-piece
  • some bags can detach or leak from the coupling
  • mechanical couplings are not ideal for hernias

Closing Thoughts

So which option is better for you? That’s probably something you’ll need to investigate yourself by sampling products from various manufacturers. You may even decide to switch between systems depending on your plans for that week or month.

Question: Are you a fan of one-piece or two-piece ostomy systems? Why/why not?

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I used to be a very happy user of Convatec 2 piece with snap fit. Unfortunately, the plastic ring began giving me skin irritation. Only fix was to shift to 1 piece, Hollister soft convex. Trade off is that while it isn’t as convenient to line up wafer hole, the more flexible one piece seems more resistant to pancaking.


Thank you for very clearly explaining the difference between a one and two piece system. I’ve been using a two piece Convatec system for several years, and they last an average of 5-7 days, depending on how often I shower. I would like to know if you have had any experience with a waterproof cover I would love to shower every day, but the wafer just doesn’t hold up for more than 2-3 days. That gets too expensive for my budget to handle. Thanks for listening


With the two piece system how many days can i use one pouch? And the wafer?


2 pc is the way to go now i just have to convince my insurance company. and put the case of one pc leak bags on ebay


I like the two piece as I use the disposable liners that are so great and easy.

Juraj Gašparík

Prosím vysvetliť načo je na ileostomickom jednodielne vrecku Sensura Mio 16415 maxi krúžok, ktorého vrch sa nedá odlepiť a preto sa neviem zbaviť tlaku v sáčku. Dočítal som sa , že ten krúžok vie znížiť tlak až o 61%. Len neviem kedy a či sa dá NATO spoľahnúť, keď sa mi po 1-2 hodinách nafúknuté sáčok s či mi nepraskne resp.nevytlačí obsah sáčku. Ďakujem. Gašparík.

Sue Hill

I use a two piece that clips together, at first I found it a little bit bulky but then I accidentally found a great benefit. Because the bag is bulkier it gives my stoma that little bit more space (specifically height so it isn’t as squashed), and this has solved the majority of my pancaking problems :-)
I’ve never (touch wood) had a problem with the bag popping off the base, it’s very secure.
The bag has the loops so at night I can wear a tight belt to hold the bag into place which (touch wood again) has stopped leaks when the bag gets full


I like the one piece for the low profile but if I could only have one system it would be the two


I have used both methods and find the one piece is like going in blind!!!needless to say I use two piece system