I have 2 pet rat girls (very energetic ones at that). These clip in ledges really help to keep them entertained and also give them something sturdy and hard wearing to chew on. My girls love to sit and chill on these woven hammocks and they are always waiting there when I come home from Uni.
This product is great quality, its been through my washing machine several times and is still holding strong. It has survived 2 young rats set of teeth ever since they were born, and the genius clips make it easy to move around the cage to keep the rats exploring.
TIP: stuff bits f tissue paper in the gaps and they love to pull them out and make a nest. It also means, if you have several and line the ceiling of the cage with them, that the rats have to keep moving the paper around, giving them more exercise and keeping them occupied when i'm in classes.
I would recommend getting several of these as they're a great investment and will last you ages.