These are the round EVA Foam Inserts for the Revolve cases.  You have the option to choose the insert with 3 rings pre-cut to allow for any size belt storage.  The dimensions are 12", 2", 2".  Or, a full 16" round piece which allows for full customization of the entire insert.  If customizing this piece for an impact driver, a complete set of tools or items larger than 12", the 16" insert is the one we suggest.