The Dexcom G6 Continuous Glucose Monitoring (CGM) System measures glucose levels using a sensor inserted just underneath the skin and a transmitter that is affixed on top of the sensor, which wirelessly transmits glucose readings up to every five minutes to a receiver or compatible smart device.Part of the Dexcom G6 Continuous Glucose Monitoring (CGM) System, G6 Sensors are factory calibrated by entering the sensor code in to the display device. Enjoy up to 30 days of continuous glucose monitoring with each Sensor 3-Pack. Sensor features include: Factory-calibrated Convenient one-step insertion with the new auto-applicator 10-day wear This product is only compatible with other Dexcom G6 products and compatible smart devices†. *Compatible with the Tandem t:slim X2 insulin pump