It is the perfect size for our cage. Mr. Nibbles uses it pretty well, although sometimes he just doesn't use it and i have no idea why. But it's nice because it stays in place and he doesn't toss the litter around.
Good size, hooks to cage, wire screen keeps the rat out of the litter
Is a little tough to get installed at times, but if you hook one side up and then push the cage in on the other side, you can get the second hook attached.