Crystal materials: 99, 996% of Al2O3, High Purity, Monocrystalline Crystal quality: Block marks, twins, Color, micro-bubbles and dispersal centers are non-existent Diameter: 50.8, 0.1mm Thickness: 430, 25um Orientation: C-plane Primary flat length: 16.0, 1.0 mm Patterned spec. Diameter: 2.4 , 0.2m; spacing: 0.6 , 0.2m; depth: 1.5 , 0.2m TTV 10um BOW 10um Warp 10um Front Surface: Ra< 0.2nm (By AFM) Back Surface: Fine ground (Ra=0.5 to 1.2 um). Cleaning/packaging: Class 100 clean room cleaning, vacuum packaging; 25 pieces in one cassette or single packaging.