It does not need a bag. You can just empty the container into the trash. But if you do want some, these should fit: Homava Dust Bag Roborock

These fit in there: Roborock Dust bag (3 -part)

If you have the model with a transparent container, like this model, you need the 1.8L bag for it. Actually, you don't need a bag, but there is an attachment included that you can use to fit a 1.8L bag instead of the metal filter, and it will easily last for a month. A bag is also included.