I have (3) 14 day freestyle libres. They all expire 12/31/23 All brand new with seal. If you have any questions feel free to ask! The FreeStyle Libre 14 day system is a continuous glucose monitoring (CGM) system consisting of the FreeStyle LibreLink app* and a glucose sensor worn on the back of the upper arm. FreeStyle Libre 14 day sensor How does it work? The sensor uses a thin, flexible filament inserted just under the skin to measure glucose levels every minute. How do you use it? Use your smartphone* to scan the glucose sensor with a one-second scan to replace fingersticks.