Dexcom G7 15-Day CGM Sensor. 1 SensorTake control of glucose with fewer sensor changes. The Dexcom G7 15 Day Sensor delivers real time continuous glucose monitoring for up to 15 days, plus a 12 hour grace period to make sensor changes easier. This is the 15 day version of Dexcom G7 cleared in the United States for adults 18 years and older with diabetes. WHY CUSTOMERS BUY THIS Fewer changes per month More uninterrupted data More flexibility at change time with the built in grace period