John M.wrote a review of Therm-a-Rest Down Coupler on November 15, 2012
Familiarity: I returned this product before using it
I bought this item thinking it would make my mattresses a little more comfortable by adding some loft. Unfortunately, this is very thin and only has about 1/2" of loft, which compresses to nothing when you lay on it. I could see the coupler being a benefit in the summer as the bottom part of a sleep system but don't see it adding much warmth to a non-insulated mattress in cold environments. It is has significantly less loft than a sleeping bag and didn't improve comfort of my mattress.