THIS CAN ALSO BE USED ON NORMAL STIHL STRAIGHT SHAFT FS WEEDEATERS (LIKE FS90R FS91R FS111R FS110R FS131R FS130R) AS LONG AS YOU HAVE A SOLID INNER DRIVE SHAFT. IF YOU HAVE A SOLID INNER DRIVE SHAFT YOUR TRIMMER IS SET UP TO BE ABLE TO RUN OTHER ATTACHMENTS ON YOUR WEEDEATER RATHER THAN ONLY A STANDARD WEEDEATING HEAD. CAN HOLD UP TO A 16 BAR, BAR SIZE REQUIRED IS 3/8 PICCO.