These do wear out but mostly the pets get ahold of them and chew a little causing a leak. I always keep an extra replacement around even though I don't need it very often. Great that you can replace just this part instead of having to buy a new bottle.

Pros: easy to replace

Cons: none

We had 3 rabbits and eventually one of the water bottles would leak. We were never able to find the rubber replacements so that meant buying a new bottle. I am glad that these are finally available to keep on hand.

Pros: Work great

Cons: Never knew replacements were available

It's nice that they offer replacement stoppers so you don't have to buy a whole new water bottle. They help prevent leaking. Great idea that saves money!

Pros: Nice replacement part

Cons: Can get chewed up

It's about time companies have started offering replacement parts. These bottles we have gone through so many and to be able to reuse them is wonderful!

Pros: :)

Cons: :(

we have their water bottle. ITs the only one that we tried that doesn't leak

Pros: great bottle

Cons: na