Lyle is correct in that the old ensolite pads were vanilla in color and had a rubbery feel to them. A full size pad was 20" wide x 72" long x 3/8 thick; weighed one pound on the nose; and they were extremely comfortable. They were rated for well-below-zero weather, and would keep you quite warm at 0*F for those concerned with R-ratings. I’ve used them on snow and been toasty.
Ensolite was developed by NASA to absorb pressure, which may explain why it is so comfortable even at only 3/4 of an inch thick.
Having seen “blue pads” I do not think they are made of ensolite.
Having seen Ridgerest and Z-Rest pads I do not think they are made of ensolite either; neither do I think they would be as comfortable in terms of cushioning. In short, the Ridgerest and Z-Rest pads are all thicker, being .5 or .625 or .75 inches thick, appear to me to be less comfortable than the old ensolite pads in terms of cushioning and warmth, and at 20" by 72" are heavier than the old ensolite pads.
This is why I’m wondering what happened to them–why did ensolite pads disappear? They strike me as a better product than the current closed cell foam sleeping pads.
Conan
Conan