diff --git a/docs/property-pages/controls/number-box/index.md b/docs/property-pages/controls/number-box/index.md
index ec1d9ca3..2d0a05af 100644
--- a/docs/property-pages/controls/number-box/index.md
+++ b/docs/property-pages/controls/number-box/index.md
@@ -16,3 +16,11 @@ Style of the number box can be customized via the **NumberBoxOptionsAttribute**
 ![Number boxes with additional styles allowing specifying the units and displaying thumbwheel for changing the value](number-box-units-wheel.png)
 
 {% code-snippet { file-name: ~PropertyPage\Controls\NumberBox.*, regions: [Style] } %}
+
+#REMARK on Number box units. 
+Use 0 for not using units. 
+If units are specified then the corresponding current user unit system will be used and the corresponding units marks will be displayed in the number box. 
+Regardless of the current unit system the value  will be stored in system units (MKS)
+
+![image](https://user-images.githubusercontent.com/979361/132507448-2858fdb2-a1b6-4f29-aa16-57c3fc9a5563.png)
+