There are many many hole in the steralite bin cover but you can't see them because of the flash and the cage above has feet so there is air flow to the bin cage. I used a 90 quart bin that costs about 11.00 from walmart, had the hubby fix the wheel to the side of the cage, and added the wire cage on top. A syrian hamster Piglett lives in here. I got him in January as a baby.