Step tread size on new HW296 double ste

[Cowboy6201]

I need to put carpet step treads on my new HW296 2017.
My Dog got 2of his nails caught in the holes on my HW296 and broke them, the Vet had to remove them, luckily their growing back in fine, WOW that hurt him.
So I need the carpet treads so this can't happen again.
Are they 18" 20" 22"?

[SeaDog]

You can find the tread covers at almost any camping store or amazon, mine are held on by springs and Jake has no problems.