The mattress pad came vacuum tightly so as recommended in reviews I let it stay out and "air" for 48 hours flat on the floor. It filled in slowly and was pretty much uniform but there is (still is) a small seam area in middle that did not fill out like sides? But it is still very soft and comfortable and size is exact. A full size mattress cover fit it well. As I also saw some reviews stated not exactly 3 inches and I agree, it is a bit less but still was plush enough to use on my pull out sleeper couch purchased here as well! Overall very pleased!