We have a pretty big tank for our gerbils, so these extra long ladders are fantastic - We took the metal hooks off and anchored one end with a rock and the other end we just rest it up against the tank wall. Another ladder we positioned one end on top of a house made by the same company and the other end rests on a tile shelf we glued to the tank wall. Our gerbils are full sized and the ladders are very stable - they spend a lot of their time on these ladders getting around their environment, and they like these much better than the bird-type ladders we had before.