I bought it for extra protection of the playpen mattress because the existing one was already hard and uncomfortable, both for playing and for a few hours of sleep.
The dimensions fit perfectly in a square playpen 90×90.
I like that it has thickness and it is not flat, and also that the fabric can be removed and washed.

Exactly in the dimensions of the park we had bought from jumbo a few years ago, which is square so we did not face any problem