Freestyle Libre 14 Day Sensor Total Diabetes Supply The FreeStyle Libre 2 sensor will only work with the FreeStyle LibreLink app You may continue to use the FreeStyle Libre sensor with the FreeStyle Libre reader if you do not have a compatibleThere is no needle in a Libre sensor only a thin filament 2, level 2, 1 yr ago, I think he means the needle for initial insertion, 3, level 1, 1 yr ago, The filament is 04mm thick, which is the only Freestyle libre 2 sensor needle size