Ikea Trofast / Flisat Activity Lid 

A fab Large Sensory tray which fits into the large trofast bins
(40x30 sized trofast tray)

It comes in two pieces, a 3mm backing piece with little windows cut out and then a hollow 6mm piece which you can then glue to the base if you wish (Any white craft glue works well) 

Pop lights underneath to shine through the windows and doorway ! 

The top layer is 6mm deep and perfect for sand to create a real sandcastle effect !