Protect the floor of your tent and extend its useful life. It's sized to fit the floor of the Big Agnes Chimney Creek 4 mtnGLO Tent and designed so it doesn't channel rain under the tent.
The standard test for coated fabrics uses a standing pipe (column) filled with water. The figures given are the water column height. A 1000mm coating allowed no leaks after 1 minute under 1000mm of water.