diff --git a/dumux/material/spatialparams/porenetwork/porenetwork2p.hh b/dumux/material/spatialparams/porenetwork/porenetwork2p.hh
index 8ec48f9de5649117a959cabd70ec2f3382672d1f..7876af25c66c1a447cb6a12e8df070db331543de 100644
--- a/dumux/material/spatialparams/porenetwork/porenetwork2p.hh
+++ b/dumux/material/spatialparams/porenetwork/porenetwork2p.hh
@@ -157,7 +157,7 @@ public:
     }
 
     /*!
-     * \brief Returns the surface tension \f$ N/m\f$
+     * \brief Returns the surface tension \f$ [N/m] \f$
      *
      * \param element The current element
      * \param scv The sub-control volume inside the element.