What does the term disconnect refer to?
This refers to how the parts of the slide come apart. Half of a slide will attach to the cabinet, the other half will attach to the drawer. If you want to remove a drawer to clean you will need to disconnect the drawer half from the cabinet half of the slide in order that the drawer can be removed from the cabinet. Different groups of slides will have different types of disconnect features for removing one half from the other. Some slides may have no disconnect feature.