Installing a couple of these has enabled me to replace the bars of my guinea pig cage with perspex panels, which in turn has slightly reduced the amount of hay and poop my guinea pigs can kick everywhere. I was a little worried that they might knaw on the new holder now it was physically in the cage but after a solitary experimental nibble in day 1 they have concluded they can't eat it and now they leave it alone. Also makes changing the water so much quicker as the bottle now just slides in and out.