Although this cushion is very comfortable, I had need to modify its shape to fit my needs. So I removed the cover so I can trim it to fit, and will sew the cover back on when finished. I was surprised to learn that only the top inch is actually memory foam. It is glued to 3" of "normal" foam rubber. So if you are expecting this cushion to be "ALL" memory foam, it is not. But it is very comfortable. I have another one that is XL size which nicely covers the seat in my office chair and helps a lot with Sciatica due to a crushed disc in a car accident many years ago. I can sit longer comfortably because of these cushions.