I use the Nemo Fillo. It has a 1-inch foam layer and a blow-up air part. (And an elastic cord on the back that you can put a shirt or something in if you want it even thicker, though I don't think you'd ever need that in a hammock; I don't even blow it up all the way in the hammock.) Soft microsuede cover that's removable and washable. And it packs down pretty small. Love it!
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