No outer cover - insert filled with wool only. Allows you to purchase your own outer cover to customize the bed for your pup and also keep the outer cover washable. Lots to choose from on Molly Mutts website or you can also look on Amazon for some other options that fit the dimensions. Never used - my Dog won't leave his old bed that I am trying to get rid of even though this one is so much more comfy and will last so much longer. Dimensions: 36” l x 24” w x 2.5” h (this is what is stated on the MM website but I find that the actual bed is MUCH fluffier and sits much higher, right now at like 6-7 inches high, but I know over time this will reduce. It will still fit in a 36x24x4 cover from Amazon.) Unlike many dog crate pad fillers on the market, these wool inserts are nontoxic, 100% all-natural, and chemical-free. Wool is naturally thermoregulating, so pets stay cool in summer and warm in winter. Molly Mutt only works with farms that have strict growing standards: - sheep are rotated amongst a number of pastures to allow vegetation to recover from grazing - encourage alternative medical care to keep the sheep healthy with the fewest chemicals possible - no herbicides or pesticides are used in the fields where sheep will be grazing - to go even further, the wool is randomly spot-tested for harmful chemicals - wool from the sheep's bottom & belly are separated and sold to other customers See photos for more info or send over any questions you have