| Substrate Material: | Crystal sapphire(C plane); Optical grade | 
| Design: | Cube design with all 6 surfaces optically polished Optical surfaces: S1, S2, S3, S4, S5 and S6 | 
| Outer Dimensions: | 10.0 x 10.0 x H10.0, +/-0.1mm | 
| Surface Quality: | All surfaces(S1/S2/S3/S4/S5/S6): 40-20 S/D | 
| Parallelism: | S1/S2, S3/S4 and S5/S6: within 3 arc minutes | 
| Surface Flatness: | <Lambda/4@ 633nm over surface | 
| Bottom Surfaces(S5 & S6) | C-plane surfaces, 40-20 S/D, <lambda/4 @ 633nm | 
| Angle Tolerance: | +/-5 arc minutes | 
| Bevels: (fine ground) | 
S1 ~ S4: all these 4 surfaces with standard bevelled edge of 0.2mm x 45deg Bottom Surfaces(S5 and S6): S5: C-plane surface with bevelled edge of 0.5mm x 45deg 
S6: C-plane surface with standard bevelled edge of 0.2mm x 45deg |