I have carried a Gossamer Gear 1/8" Thinlight Insulation pad for over five years. This super light foam pad has been great for many uses during the day and night. I have used it as my sit pad on every imaginable surface, for my mid day napping pad under trees or on picnic tables, as a shared sit pad for groups of stinky hikers, for a lunch table, as cowboy camping protection underneath my inflatable sleeping pad, as added insulation in my hammock and to wrap around fragile items that I sometimes carry in my pack.

My first Thinlight pad traveled with me for the entire 2650 mile length of the Pacific Crest Trail. After three years I finally replaced it with a new one which I used for a thru hike of the Hayduke Trail. I carry the pad on the outside of my pack so I have had to make many duct tape repairs from tears caused by some serious bushwhacks through cactus and thorn bushes. If I were to carry inside of my pack it would probably still be in great condition.

It is a durable closed cell foam which is super flexible, will not absorb water and is incredibly light weight. The 1/8" inch thick pad weighs about 2.5 oz and is around 20" wide and 59" long. It is an inexpensive option for a lightweight minimalist pad that can be used for many purposes and an item that I will carry on all of my backpacking trips.

http://gossamergear.com/thinlight-insulation-pads.html