We haven't had this mattress pad for long, so it hasn't been tested out much. I got it to protect our new Sleep Number from spills or accidents with our 2 year old and our dog. There was a review that mentioned that it fit her Sleep Number mattress, so that is one of the main reasons I bought it. I does fit and I pray it protects as it claims.
With a potty training toddler that occasionally sleeps in our bed, this was the perfect solution to protect our new bed! There is no extra padding here, but the topper has a terry cloth like texture so it kind of grips the sheets so things don't slide around.