Small piece of upholstery foam (Rearsby LE7)

Hi, I’m wondering if anyone has a small piece of upholstery foam, I’m looking for something around 2inches thick and it needs to be 39cm x 42cm. It’s for the top of a piano stool I’m refurbishing. I thought it might be a small enough piece to be an off it I can put to use. Thanks in advance!