1 inch bar spacing

I was looking at buying a new cage for my rats and I came across this one cage that I thought was pretty good for them.

Topeakmart 52" Height 6 Level Ferret Rabbit Small Animal Cage Hutch Indoor with 3 Front Doors & Wheels Black

The only thing that threw me off is that the bar spacing is one inch. Mr rats are about 5 months old and still pretty small. I don't have a good picture to show size but small enough that I'm a little worried that they can squeeze through those bars.
Help?

No idea what you cage looks like or the dimensions

You can cover the outside of the cage with hardware cloth
It is less then ideal, and can rust but people do that

because of the possibility of predators etc entering your home you will want to keep the hardware cloth on the cage regardless of how large your ratties get

Big rats can live in 1" bar spacing...but small ones will escape.