tl;dr short version: these refills can work perfectly for the Original LitterLocker, but only if you take an old LitterLocker refill and remove the guts to allow this Mama Bear Diaper Pail refill to fit INSIDE the outer shell of a used up LitterLocker refill. See annotated pictures for instructions.Long version:We've used the original LitterLocker since 2010 (not LitterLocker II -- that came later and is terrible), and in my opinion, it is godsend for cat owners everywhere. Unlike the LitterLocker II, it actually does seal away odors, and makes the job of dealing with indoor cats litter cleaning immensely easier.So when I found that we could no longer get refills for the original LitterLocker--that they were flat out discontinued--I was very sad and upset. Way more than probably fitted the occasion, I suspect! I watched with deepening despair as we used up the last of our refills, and nothing I was finding online in terms of replacement systems for dealing with used cat litter was making me feel any better. Then it dawned on me to start looking into the systems used by parents to deal with diapers, and that's when I stumbled on these refills, and found one reviewer who said that they worked for the original LitterLocker! I was cautiously happy and hopeful! And I ordered a 4 pack.When they arrived however, we found that they were just slightly too small and would get pulled through into the bottom section and not stay secure under the lid. I thought of wrapping some tape around the lip to make it larger in diameter, but then I thought to see if it would fit INSIDE an old litter locker, and lo and behold, it was a PERFECT fit! However, then it was too high for the lid assembly to snap onto the body of the LitterLocker. So I carefully removed some height from the old litter locker refill host, and tried again, and voila! It was perfect!So, I uploaded some pictures so you can see the process. (Apparently you can't count on your pictures getting posted in the order in which you upload them, so I added some text and arrows for clarity.) I decided to keep as much of the old litter locker refill casing as possible, but all you really need is just the outermost, topmost ring of the old litter locker refill.If you want to follow my method, take an old, completely used up, litter locker refill and remove the top horizontal ring, then make a cut about half-way down the vertical inner cylinder, all the way around. Then remove almost all of the outer cylinder that shows above the lip. If you look at the pictures you can see a side view and top view of what this should look like. The side view shows the job almost--but not quite--completed. Be careful with your cutting down of the outermost, topmost part of the cylinder above the lip. Go too far and you will cut down through the lip and compromise the integrity of the shell! Do a little bit at a time, and leave a little bit showing. You don't need to remove it entirely. It just can't be left at full height.Once you are finished, the Mama Bear refill will drop right into the LitterLocker refill host adapter, and then of course will fit perfectly in the body of the LitterLocker. And, if you remove almost all of the outer cylinder which rises above the lip of your host adapter, the lid assembly will snap on easily. (See pictures)These refills are less than half the capacity of the original LitterLocker Refills, but they are also half the price, so it's pretty much a wash. More importantly, though, once you make an adaptor for them from an old LitterLocker Refill, they work PERFECTLY! (Just remember not to throw away the adapter you made when putting in a new refill! LOL! Although, you'd remember pretty quickly when the Mama Bear refill gets pulled down inside, I suppose).I know it's stupid, but I'm so happy that we can still continue to use our two original LitterLockers! Hope this was helpful!