1. Four thicknesses of CVD graphene: Available in either 1, 2, 3-5 or 6-8 layers 2. Substrate: The Ultra-flat Thermal SiO2 Substrate consists of a 200nm thermally grown SiO2 film on an ultra-flat silicon wafer with a normal thickness of 675 µm. The size is 5mm x 5mm. 3. Graphene coverage of the ultra-flat silicon is > 75%