Offering additional protection for rugged or wet terrain, the Alto Footprints adds a 68D waterproof fabric layer under the tub floor of your tent. Makes Dry Set-up and Take-Down a breeze and allows for an easy Fly Only tent set-up for ultralight adventures. Lightfoot has the same footprint as the tent floor; Bigfoot extends into the vestibule to add additional protection for youtr gear on those wet trips.