diff --git a/kalibrierschein/kalibrierschein.cls b/kalibrierschein/kalibrierschein.cls
index 46af3670e9b519b9ee351268da91bf6a40ecae9b..7b49aa3a9b1ab855c3f403dc6eb0fd49a8031818 100644
--- a/kalibrierschein/kalibrierschein.cls
+++ b/kalibrierschein/kalibrierschein.cls
@@ -365,9 +365,14 @@
   %,per-mode = symbol
   ,per-mode = reciprocal
   ,mode = text % !!!
+  %%%,inter-unit-product = \ensuremath{{}\cdot{}}
 }%
 %%%}
-
+\AtBeginDocument{
+  \sisetup{%
+    ,inter-unit-product=\ensuremath{{}\cdot{}}
+  }%
+}
 
 
 \newcommand\resultTable[3][]{%