My DNC. Actually, it's a TCN! Lol!!! Yea, so I did have to remove it's wheels in order to fit it into the room, it actually fits with room to spare as you can see, but in order to put the third cage up on top you need to raise it higher than it actually sits as pictured so that it can be lowered into position. Anyway, it IS on little plastic bottle caps to protect the hardwood floor, and it slides much easier too. As for ideas on things to put inside it??? I have 4 shelves, with the bottom cage there are 2 placed directly across from each other in the middle adjustment position, effectively separating the cage into 2 sections. The 2nd cage is open with no shelves (I need 2 more but have never yet HAD to have them) and 3 big males sharing the cage. And finally, the 3rd cage on top has 2 shelves NOT positioned across from each other, but rather, 1vis in the bottom adjustment slots, and 1 is in the top slots, so that the 3 busybody females have lots of room to roam around in and they've made the top shelf the bedroom, the bottom shelf the bathroom, and the floor is where I feed them and they have a wheel and a box. As you can see, I use a mixture of newspapers and fleece, and litter corner trays. My setup may look a mess, but it is effective and easy to clean. And that is priority when you have a lot of rats, and cages to clean.