Generally any standard-sized backpacking pad (20″ or 25″ width) will work regardless of thickness and length. 25″ width is recommended. In general the largest commercial camping pad that will be appropriate will be the size of the Exped downmat 9 LW, which is aprox. 77″x25″x3.5″. Also keep in mind that in a hammock you need insulation, but no padding is needed so extra thick air mattresses are not necessary, R-value and warmth are what are really important. Many will find the best luck letting a good percentage of the air out. In general pads work quite well in bridge-style hammocks like our Ridgerunner but not so well in end gathered style hammocks like our XLC, Blackbird, and Eldorado…where underquilts are king.