Looking for a ground sheet that's lighter than Spinnaker fabric? The Polycryo ground sheet is constucted from industrial grade cross-linked polyolefin. This material is extremely tough for it's weight, with amazing puncture resistance. It has a tensile strength of 15,400 p.s.i. per ASTM D-883. It is waterproof, but very slightly breathable (1.09 gms of water vapor/100 sq.in./24 hours).
The ground sheet comes in two 40 x 96 " sheets. It weighs 43g per sheet about 20% lighter than the Spinnsheet ground cloth, and much more affordable. It is sold in single packets, and can be easily trimmed by the user to custom configurations.
These ground cloths are absolutely clear, so you can see if you missed any pebbles or pine cones after you put your ground cloth down. It would also serve well as a solar still in an emergency situation. This stuff is amazingly tough for it's weight, and can help shave those last few grams off your pack weight.