A footprint protects your tent floor from wear on rough ground. It's sized to fit the floor of the MEC AMP 2-person tent and designed so it doesn't channel rain under the tent. The footprint also allows a canopy-free ultralight setup.
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.