Beamsplitter CubeSpecifications: Material: BK7 grade A optical glass Dimension Tolerance: +/-0.2mm Surface Quality: 60-40 scratch and dig Flatness: lambda/4 per 25mm at 632.8nm Angle Tolerance: <3 arc minutes T/R:50/50+/-5%, for natrual light, T=(Ts+Tp)/2, R=(Rs+Rp)/2 Coatings: Partial reflectance: on hypotenuse face AR-coatings: on all input and output faces.