The Dymo LabelWriter Spool is made of 2 parts. The main part is a black circular disc with a spindle protruding from the middle of it. The other part is a black disc with a hole at the center. The disc slides over the spindle and locks the label roll into place. Why would I need a replacement spool? The LabelWriter spool is made of hard plastic and they don’t break easy. In the unlikely case that you do happen to break yours, then it’s simply a matter of ordering one from Labelcity.com…. Read more about Dymo LabelWriter replacement spool.