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Leica GMP004 L Bar Mini Prism

Image of Leica GMP004


Professional Series 1000

The Leica GMP004 L Bar Mini Prism is suitable for permanent monitoring applications where less range is acceptable. GMP004 Mini Prism is fixed in a metal housing, supplied with an L-bar for easy installation.

The prism assembly is made out of Grey Anodized Aluminium.

The GMP004 is less robust than the GMP104, so if a monitoring prism in more challenging environmental conditions (e.g. extreme temperatures or very wet environments) is needed, the GMP104 is recommended.


Absolute constant: -25.48 mm
Leica constant: +8.92 mm
Mount:Screw Holes


  • EDM Range: 1000m
  • ATR Range: 600m
  • GMP004 doesn’t have Anti-Reflective Coating – there is a possibility of distance errors below 20m if prism is not tilt perpendicular to sightline

Leica GMP004 FAQ

Below is a list of frequently asked questions about Leica GMP004.

What is the prism constant for the Leica GMP004?

The absolute prism constant (true value) for the Leica GMP004 is -25.5mm. The prism constant as defined for Leica instruments for Leica GMP004 is 8.9mm. For a more detailed explanation on prism constants please see this article.

Can I use the Leica GMP004 with a Leica instrument?

Yes, you can use the prism with a Leica instrument as long as you set up the correct prism constant in the instrument settings.

What is the prism constant value that I need to use with a Leica instrument?

In order to use the Leica GMP004 with a Leica instrument you should use 8.9mm as the prism constant value.