We're working out what we think - we'll add our view here!
Snow Peak says:
The Lago Pro. Air Groundsheet is a water resistant ground sheet for the Lago Pro. Air Tent. The sheet allows for protection from the cold and wet surfaces in which you may be setting up your tent on.
We're working out what we think about Snow Peak's Lago Pro. Air 1 Groundsheet, we'll add our comments here in due course.