Add Units To Shipping Dimensions
When using the Modify tool to make changes to Shipping Dimensions (i.e. Length, Height, Width, Weight), you can add units of measurement in the editor.
You'll notice when you select one of these as your Google Attribute, the rule type is set to Shipping Dimension.
Here, you can enter both the number value of your dimension, as well as choose a unit of measurement from the Metric drop down menu.
So if you're editing Shipping Height, for example, you can set your unit of measurement to either inches or centimeters.