Bought this to replace a 4inch topper that was 5 years old. I was disappointed when I opened the package and found out that the "fingers" reach to 4 inches but the "valleys" are about 1/2 inch. Our previous topper was a solid 4inch, I wish I had spent the extra money and bought one of those. Once the topper is unwrapped and unfolded there is no way to rewrap it for a return. When comparing toppers, I would say this one is on average 2 inches.