2 Pcs Polyethylene Foam Sheet 12 X 8 X 2.1 Inch Polyethylene Foam Insert
Material: Polyethylene foam.
Zhaoyao Pick and Pluck Foam Inserts 8-Pack 16″x12″ Black Craft Foam
You can slowly peel the outline out directly with your hand against the grid lines on the foam sheet, or you can use a knife to cut the foam sheet into the shape you want.