Nice small size... good for cobblestones. Use as a stencil, cut it apart or use whole as a background.
Update see below for a new smaller version of this sheet!
Lightweight chipboard (which makes it a little flexible — good to wrap around curves/corners when stenciling).
If you're planning to use the stencil a lot, I would use spray shellac to seal the stencil before you get paint on it (an oil-based varnish, rather than a water-based acrylic spray will last longer). Spray a few layers and let dry. Flip it over and do again.
8-1/2" x 11"