Continuous glucose monitoring (CGM) is done with a data transmitter with a small sensor that sticks into the skin. Glucose readings are taken evey few minutes and can be transmitted to an insulin pump. The transmitter and sensor need to be changed every 10 days.
However, CGM glucose readings need to be calibrated twice a day using a standard glucose meter and test strip with blood taken from a skin prick.
The one I wear is a Dexcom. It has a patch with a Bluetooth transmitter that sends updates every 5 minutes to my phone. No calibration needed. Have to replace the patch every 10 days.
Much better than jabbing myself.