Probes for surface estimates
| Probe | Tissue | Orientation |
| Cycloids for Sv | Thin | Vertical section |
| Isotropic Fakir Method | Thick | Preferential tissue section |
| Merz | Thin | Isotropic section |
| Optical Rotator | Thick | Isotropic/Vertical section |
| Surfactor | Thick | Isotropic section |
| Vertical Spatial Grid | Thick | Vertical section |
| Weibel | Thin | Isotropic section |