Brian M.wrote a review of Black Diamond Tripod and Lightsabre Bivy Footprint on May 24, 2010
I've always considered a ground tarp / footprint to be essential gear. It adds only a little weight to your setup but will extend the life of your tent by leaps and bounds. I've also never punctured a sleeping pad, and I attribute that to always using a ground tarp under my tent. If you don't want to spill a bunch of money for this exact piece of equipment you can accomplish the same goals with a sheet of plastic like a tarp, an old shower curtain, etc.