The Sensor is applied to the back of the upper arm with a simple, disposable device called an applicator. When the Sensor is applied, a small (5mm) filament is inserted just under the skin, and held in place with a small adhesive pad. Most patients don't feel pain when applying the FreeStyle Libre Sensor.^† 

^†Data on file. In a study conducted by Abbott Diabetes Care, 93.4% of patients surveyed (n=30) did not feel discomfort under the skin while wearing the Sensor.