Tyvek Groundsheet 5' x 9'

The 5x9 footprint is just right for my bivy, and it's shed a heavy downpour without a single drop soaking through. Weighs next to nothing in my pack, which is exactly what I was hoping for.

Packed this under my tent last weekend on a wet, muddy trip and was amazed that the bottom of my gear stayed bone dry. The material feels tough enough to handle sharp rocks, yet it weighs practically nothing in my bag.

I've been using this as my groundsheet for the last few trips and it's held up great against sharp rocks and roots. It folds down small enough to fit in the bottom of my pack without adding noticeable weight.