Roof prism is combined with a right angle prism and a totally internally reflecting roof and they are attached by them largest square surfaces. It can invert and reverse an image, also, deflect the image 90° . Therefore, it is often used in terrestrial telescopes, viewing systems and rangefinders.

| Material: | BK7 Grade A Optical Glass |
| Dimension Tolerance: | +0.0, -0.2 mm |
| Clear Aperture: | >80% |
| Angle Tolerance: | ± 3arcmin |
| Flatness: | l/2 @632.8 nm |
| Surface Quality: | 60-40 scratch and dig |