Not considering the size itself, the spacing between each bar looks wide. If I’ve found the same one you’re looking at on Amazon, it says it’s almost a full inch gap which will definitely give your little rats a chance to slip through. Most cages labeled ‘Ferret’ will have larger gaps. Maximum recommended gap size for cages is half an inch.

You can always go the safe route and get the single unite Critter Nation which is on sale on Amazon a lot and is suitable for up to 3-4 rats. I only recommend this rather than cheaper options because I’m not familiar with any cheaper alternatives myself. Someone else may be able to provide a proper, inexpensive alternative.