Selection sets are a customized grouping of multiple entities that can be saved and accessed in the FeatureManager tree to be referred to throughout the design process. They are handy when a specific set of entities of a part or assembly are being accessed frequently during the design process for things like suppressing or unsuppressing features, hiding or showing parts, adding an appearance to all features or parts, etc. They can be used in either the part or assembly level. Some things that can be placed in a selection set are edges, faces, features, and parts (when in an assembly). This video will also go over creating and managing selection sets.