The pentagonal prism has two important characteristics: First, although the light is turned to 90°, the image plane has neither rotation nor specular reflection. Second, it is a fixed steering angle device, that is to say: all transmitted light rays are turned by 90°, so it is a key component of rangefinders and can also be used in SLR cameras. The reflective surface of the prism is aluminized and protected with black paint.
| Material | H-K9L or upon request |
| Angle Tolerance | ±3’ |
| Dimension Tolerance | 0/-0.1 |
| Surface Accuracy | λ/4 |
| Surface Quality | 60/40 (S-D) |
| Clear Aperture | ˃90% |
| Bevelling | 0.2±45° |
| Coating | AR/BBAR+ reflective surface Al |
| Paint | GT-7 or upon request |
