Inner tent for the Amazonas frame tent made from 150g/m2 cotton fabric (probably, the manufacturer is being a bit cagey. Maybe it's made from the finest silk shot through with gold and platinum threads, but I doubt it). Built in groundsheet to stop the damp and bugs from rising up in rebellion against you while you sleep. The partition fits to one side of the central area so you could create a sleeping area either side whilst still having a central area to sit in and gaze out at the lovely summer weather we have whilst staying dry..