Much bigger than in the picture but fits in my Ferplast 120 cage really well. I was impressed with it until I put it in the cage and realised it was not very stable - put some food on the top bit to encourage my two guinea pigs to climb up - one of them put one leg on it and the steps shook and the food fell on his head! Going to try to fix it to the sides of the cage in a couple of places to stabilise it. My guinea pigs are male and quite big but I thought it should have taken their weight.
I ordered these for rats too and they're a really good size, I'm sure our lot will get hours of joy out of them!
The thing which lost them marks however, was the fact that I opened the packet and loads of sawdust fell out onto my living room floor! I shook the stairs out outside and brushed them down, but I'm still going to have to give them a good wash before putting them in the cage. Rats have very sensitive respiratory systems, so they're not suitable if they're really dusty.