Id been looking for a replacement of the old style Serta memory foam dog bed that uses shredded rather than mattress-style memory foam and this is the closest Ive found! The bed arrived pretty hard and lumpy, but unzipping the back and removingfluffing the inside pieces seemed to do the trick. There didnt seem like a lot of memory foam pieces but they must be expanding because this bed is PLUSH! The dimensions seem to be for the whole bed and not just the interior inside the bolsters, so keep that in mind when deciding size. My very lean 50 lb Pyrenees mix just barely fits in the Large, and the 70 lb German Shepherd can just squeeze in too but its a tight fit. As things compress more from use it might be a better fit, but if your dog likes more room you might want to size up. Overall Im  very pleased so far, I might order the XL at some point to try that out too.