UDesign support Product Unit as one of WooCommerce feature. This would be often used for variable product in single product page. The customers could know more accurate price per unit for product thanks to our Product Unit feature.
Theme Options > Features > Product Unit and enable the feature.
Then, you can notice that the Unit attribute is already created in WooCommerce product attributes list. Please add terms to this attribute.
After that, you have to add this attribute for the variation product.
Thus, you can get the result like this.