>>568998A top quilt is just a down quilt that you use as your top layer of insulation. It wraps around you while your in your hammock and its pretty much as if you had an unzipped sleeping bag wrapped up a round in your hammock.
A down quilt is a quilt of down that is cut and conformed to be suspended below your hammock. It prevents convection from stealing your warmth and helps insulate your bottom.
Pretty much you turn into a cocoon made of down. Its much more comfortable than just sliding in a pad and If you do it right should be compact and weight less than your standard sleeping bag and pad combo.
