Navy Round Cushion with Zipper

Received this from the obstetrics department. It's new and unused as I didn't need it this time.
It seems the cover is removable as there is a zipper all the way around.
There is a U-shaped indentation.
I'm not sure of the material, but I believe it's a high-resilience type.

Approximately 44cm x 34cm x approximately 6cm (indentation approximately 4cm)
Navy ring cushion with zipper.

- Color: Navy
- Features: Zippered cover

Maternity, prenatal, postnatal, postpartum, donut cushion