
Description
The Topcon Dual L-Bar Mini Prism (monitoring) is a monitoring prism made by Topcon (part number 1042646-01).
Its absolute prism constant is -8.5 mm, which is +25.9 mm on the Leica scale.
Specifications
| Model: | Dual L-Bar Mini Prism |
| Manufacturer: | Topcon |
| MPN: | 1042646-01 |
| Status: | Current |
| Absolute constant: | -8.50 mm |
| Leica constant: | +25.90 mm |
| Constant source: | Manufacturer documentation |
| Dimensions (W × H × D): | 90.5×90×43.2 mm |
| Weight: | 260 g |
| Maximum range: | 1,200 m (Up to 800-1200 m; minimum 1.5 m (same conditions as datasheet footnote)) |
| Mount: | M8 adapter thread |
| Coating: | Silver |
| Last verified: | 21/10/2026 |
Sources
Topcon Dual L-Bar Mini Prism (monitoring) FAQ
Below is a list of frequently asked questions about Topcon Dual L-Bar Mini Prism (monitoring).
What is the prism constant for the Topcon Dual L-Bar Mini Prism (monitoring)?
The absolute prism constant for the Topcon Dual L-Bar Mini Prism (monitoring) is -8.5mm. The Leica constant is 25.9mm.
Can I use the Topcon Dual L-Bar Mini Prism (monitoring) with a Leica instrument?
Yes, just set the prism constant to 25.9mm.



